Best way to migrate from old MB Air to New M1
My grandson uses my 2011 MacBook Air running High Sierra 10-13-6 and I am treating him to a new M1 for Christmas to help him with his studies. He has a Timeshare backup but by using this am I right in thinking High Sierra will be installed on the new machine and Big Sur will be removed, if so what would be the best way to transfer the existing programs and files onto the new machine?