What instructions should you give your barber to ensure they cut your hair in accordance with halacha?
Don’t cut the payos (sideburns) area too short
Can some hair be removed from the payos area, or does the entire area (temples to bottom of hear) have to remain fully intact?
It’s hard to know the exact length.
The Ramba”m is ok with just three rows of hair which would be barely anything.
People have usually said to the bone.
Figure about halfway alongside the ear is the accepted Minhag. It’s not the end of the world if you cut it a bit higher, if you do not use a razor.
(But certainly not higher than the Ramba”m)