There are two cabinet files (.cab) needed:

• microsoft-windows-netfx3-ondemand-package~31bf3856ad364e35~amd64~~.cab
• Microsoft-Windows-NetFx3-OnDemand-Package~31bf3856ad364e35~amd64~en-US~.cab

In Server Manager "Add roles and features" must be selected, then click on next

1. In Server Manager "Add roles and features" must be selected, then click on next
2. Select "Role-based or feature-based installation" and click on next
3. Select the server from the server pool and click on next
4. From the list select Web Server(IIS) -> Web Server -> Application Development
5. Tick .NET Extensibility 3.5 and ASP.NET 3.5 and then next and accept the required dependencies ISAPI Extensions and ISAPI Filters
   
6. Under .NET Framework 3.5 Features tick HTTP Activation and Non-HTTP Activation then next and accept the required dependencies Configuration APIs, .NET Environment 3.5, and Process Model.
   
7. Select the "specify an alternate source path" option and choose the folder where the files above are and click on Install