What is the .NET Framework
.NET Framework is a set of development libraries from Microsoft. It is installed with the latest versions of Windows. Multiple applications use them so most likely their are already installed in yours Windows.
In case of absence installation of these libraries in the proper version, the installer should informed you about it and redirect to the appropriate page where you can download them. If the Setup program does not start (communication with an incompatible version of the operating system), try them Download (version 4.6.2) and install it yourself.
If you're not sure what version of .NET Framework you have you can check this by using ASoft .NET Detector downloads at this address.