Hey all im back again. So soon ill be doing body work and spraying the 1000 coupe. Paintings been my nemesis but i have done good small jobs

Im looking to do acrylic as it will be done at home and its easier to work with. What stages and grits do people recommend? What grit should i use to rub down the original paint ready for primer. Also what grit should i rub before painting (so on the primer)

Ive been told to use a 120 straight up then go down to a 240 then primer 2 coats, rub to 400 and primer again. Rub down to 800 and lay top coat on