You don't, is the short answer. Especially when the thing from github is unmaintained and unsupported on the current version of qubes:

Please note I currently do not have time to maintain Liteqube, it is not updated to support Qubes 4.2.

If you're just using qubes for funsies though and safety/security doesn't really matter, the qubes docs provide a very hacky method for copying files to dom0 (prefaced with a long "you really shouldn't do this" warning): https://doc.qubes-os.org/en/latest/user/how-to-guides/how-to-copy-from-dom0.html#copying-to-dom0