Good set of clippers
...then practice on the cat, dog then finally wife before attempting to do your own.
........I'll get me coat!
But seriously, a decent set of clippers with guards, start with the longest all over, then go down one or two and do lower down, then down again. Always work into the hair, not with it. At Tim says watch some Youtube tutorials or just do as I do and go for a #2 all over, shorter at the back and sides [not that I have much ontop now anyway]. You can either taper the pack and sides or get a partner or wife to do a defined edge. Couple of goes and you will be away. Styles take a but more practice but these are utilitarian times so stick to utility cuts.
Anyway, hair grows right, cock it up and you get to try again in a couple of weeks, it's not as though any of us are attending functions and dinner parties at the moment anyway.