W10 shipped with 4.7.2 or 4.8, depending on your Windows release. If you have no other .NET versions, integrate the current .NET rollup which is
KB5004331 (Aug 2021) for the non-preview edition.
Download it from the
Microsoft Update Catalog, or NTLite's updates downloader on licensed copies. Add the file to the Updates list.
If you only have the original 4.7.2 or 4.8 distribution, you're done!
What happens if you need to install .NET 5.0? The .NET full installers are self-extracting files, we add them to Post-setup with silent install. You can't integrate 5.0 updates into the image because of that. Don't worry, 5.0 is now released every month so you've got the updated copy.
The rare case is if W10 is extremely old (or running W7-8), and you need 4.8 installed. You install the 4.8 full installer first, then apply NDP48-KB# update (also silent) immediately afterwards. Both cannot be integrated, just installed.