diff --git a/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/ComponentBusinessLogicContract.cs b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/ComponentBusinessLogicContract.cs
new file mode 100644
index 0000000..6e01abd
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/ComponentBusinessLogicContract.cs
@@ -0,0 +1,30 @@
+using TheCyclopsContracts.BusinessLogicContracts;
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Enums;
+
+namespace TheCyclopsBusinessLogic.Implementations;
+
+internal class ComponentBusinessLogicContract : IComponentBusinessLogicContract
+{
+    public List<ComponentDataModel> GetAllComponents(bool onlyActive = true)
+    {
+        return [];
+    }
+
+    public ComponentDataModel GetComponentByData(string data)
+    {
+        return new ComponentDataModel("", "", ComponentType.None, 0, false);
+    }
+
+    public void InsertComponent(ComponentDataModel componentDataModel)
+    {
+    }
+
+    public void UpdateComponent(ComponentDataModel componentDataModel)
+    {
+    }
+
+    public void DeleteComponent(string id)
+    {
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/EmployeeBusinessLogicContract.cs b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/EmployeeBusinessLogicContract.cs
new file mode 100644
index 0000000..58ddf7e
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/EmployeeBusinessLogicContract.cs
@@ -0,0 +1,44 @@
+using TheCyclopsContracts.BusinessLogicContracts;
+using TheCyclopsContracts.DataModels;
+
+namespace TheCyclopsBusinessLogic.Implementations;
+
+internal class EmployeeBusinessLogicContract : IEmployeeBusinessLogicContract
+{
+    public List<EmployeeDataModel> GetAllEmployees(bool onlyActive = true)
+    {
+        return [];
+    }
+
+    public List<EmployeeDataModel> GetAllEmployeesByPost(string postId, bool onlyActive = true)
+    {
+        return [];
+    }
+
+    public List<EmployeeDataModel> GetAllEmployeesByBirthDate(DateTime fromDate, DateTime toDate, bool onlyActive = true)
+    {
+        return [];
+    }
+
+    public List<EmployeeDataModel> GetAllEmployeesByEmploymentDate(DateTime fromDate, DateTime toDate, bool onlyActive = true)
+    {
+        return [];
+    }
+
+    public EmployeeDataModel GetEmployeeByData(string data)
+    {
+        return new EmployeeDataModel("", "", "", "", DateTime.Now, DateTime.Now, false);
+    }
+
+    public void InsertEmployee(EmployeeDataModel employeeDataModel)
+    {
+    }
+
+    public void UpdateEmployee(EmployeeDataModel employeeDataModel)
+    {
+    }
+
+    public void DeleteEmployee(string id)
+    {
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/InstallationBusinessLogicContract.cs b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/InstallationBusinessLogicContract.cs
new file mode 100644
index 0000000..af1e3d8
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/InstallationBusinessLogicContract.cs
@@ -0,0 +1,35 @@
+using TheCyclopsContracts.BusinessLogicContracts;
+using TheCyclopsContracts.DataModels;
+
+namespace TheCyclopsBusinessLogic.Implementations;
+
+internal class InstallationBusinessLogicContract : IInstallationBusinessLogicContract
+{
+    public List<InstallationDataModel> GetAllInstallationsByPeriod(DateTime fromDate, DateTime toDate)
+    {
+        return [];
+    }
+
+    public List<InstallationDataModel> GetAllInstallationsByEmployeeByPeriod(string employeeId, DateTime fromDate, DateTime toDate)
+    {
+        return [];
+    }
+
+    public List<InstallationDataModel> GetAllInstallationsByComponentByPeriod(string componentId, DateTime fromDate, DateTime toDate)
+    {
+        return [];
+    }
+
+    public InstallationDataModel GetInstallationByData(string data)
+    {
+        return new InstallationDataModel("", "", DateTime.Now, 0, 0, false, []);
+    }
+
+    public void InsertInstallation(InstallationDataModel installationDataModel)
+    {
+    }
+
+    public void CancelInstallation(string id)
+    {
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/PostBusinessLogicContract.cs b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/PostBusinessLogicContract.cs
new file mode 100644
index 0000000..9381bed
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/PostBusinessLogicContract.cs
@@ -0,0 +1,39 @@
+using TheCyclopsContracts.BusinessLogicContracts;
+using TheCyclopsContracts.DataModels;
+using TheCyclopsContracts.Enums;
+
+namespace TheCyclopsBusinessLogic.Implementations;
+
+internal class PostBusinessLogicContract : IPostBusinessLogicContract
+{
+    public List<PostDataModel> GetAllPosts(bool onlyActive)
+    {
+        return [];
+    }
+
+    public List<PostDataModel> GetAllDataOfPost(string postId)
+    {
+        return [];
+    }
+
+    public PostDataModel GetPostByData(string data)
+    {
+        return new PostDataModel("", "", PostType.None, 0, false, DateTime.Now);
+    }
+
+    public void InsertPost(PostDataModel postDataModel)
+    {
+    }
+
+    public void UpdatePost(PostDataModel postDataModel)
+    {
+    }
+
+    public void DeletePost(string id)
+    {
+    }
+
+    public void RestorePost(string id)
+    {
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/SalaryBusinessLogicContract.cs b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/SalaryBusinessLogicContract.cs
new file mode 100644
index 0000000..647ff26
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsBusinessLogic/Implementations/SalaryBusinessLogicContract.cs
@@ -0,0 +1,21 @@
+using TheCyclopsContracts.BusinessLogicContracts;
+using TheCyclopsContracts.DataModels;
+
+namespace TheCyclopsBusinessLogic.Implementations;
+
+internal class SalaryBusinessLogicContract : ISalaryBusinessLogicContract
+{
+    public List<SalaryDataModel> GetAllSalariesByPeriod(DateTime fromDate, DateTime toDate)
+    {
+        return [];
+    }
+
+    public List<SalaryDataModel> GetAllSalariesByPeriodByEmployee(DateTime fromDate, DateTime toDate, string employeeId)
+    {
+        return [];
+    }
+
+    public void CalculateSalaryByMounth(DateTime date)
+    {
+    }
+}
diff --git a/TheCyclopsProject/TheCyclopsBusinessLogic/TheCyclopsBusinessLogic.csproj b/TheCyclopsProject/TheCyclopsBusinessLogic/TheCyclopsBusinessLogic.csproj
new file mode 100644
index 0000000..a864438
--- /dev/null
+++ b/TheCyclopsProject/TheCyclopsBusinessLogic/TheCyclopsBusinessLogic.csproj
@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\TheCyclopsContracts\TheCyclopsContracts.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/TheCyclopsProject/TheCyclopsProject.sln b/TheCyclopsProject/TheCyclopsProject.sln
index 4fa5a94..72c62c5 100644
--- a/TheCyclopsProject/TheCyclopsProject.sln
+++ b/TheCyclopsProject/TheCyclopsProject.sln
@@ -1,12 +1,14 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 17
-VisualStudioVersion = 17.12.35707.178 d17.12
+VisualStudioVersion = 17.12.35707.178
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TheCyclopsContracts", "TheCyclopsContracts\TheCyclopsContracts.csproj", "{01934235-715E-4B95-B859-48E8C89DA7CB}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TheCyclopsTests", "TheCyclopsTests\TheCyclopsTests.csproj", "{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TheCyclopsBusinessLogic", "TheCyclopsBusinessLogic\TheCyclopsBusinessLogic.csproj", "{A696C749-D71B-4D1E-B2B0-1E1503F033F0}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -21,6 +23,10 @@ Global
 		{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{78C9F1B1-ABD3-4ED2-A5DC-84766DEEFC77}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A696C749-D71B-4D1E-B2B0-1E1503F033F0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A696C749-D71B-4D1E-B2B0-1E1503F033F0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A696C749-D71B-4D1E-B2B0-1E1503F033F0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A696C749-D71B-4D1E-B2B0-1E1503F033F0}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE