you no need download .NET Framework 3.5
just do this shit:
you must have Windows 10 file ISO, DVD or Bootable Flash Drive
Insert your Windows 10 DVD, or double click its ISO image, or insert your bootable flash drive with Windows 10,
depending on what you have.
extract file "Install .NET Framework 3.5 via DISM.rar"
run as admin file "Install .NET Framework 3.5 via DISM.cmd"
The file will install .NET Framework 3.5 automatically
after finding the drive letter of your Windows 10 installation media.