1. First you need to open the Server Manager on the system where you want to install the .NET Framework 3.5.
2. In the Server Manager, open the “Add Roles and Features” Wizard by clicking Manage –> Add Roles and Features.

3. Step forward to “Installation Type” and select “Role-based or feature-based installation”

4. Select the destination server for installation.

5. Click on “Features” and select the sub-feature ” .NET Framework 3.5 (includes 2.0 and 3.0)” under .NET Framework 3.5 Features.

6. Now, we get to the “Confirmation” step. Click “Install” to begin the installation.

7. Installation should have now succeed.
