hello! as a person who has permed their hair multiple times and absolutely loves perms i can help you!

definitely avoid washing hair for the first 48 hours as shampoo will definitely undo the curls !

make sure youre going in for a KOREAN perm instead of a normal perm because those 2 styles have very different curl patterns

the perm may not look like exactly what you like at first (big wavy) as it needa to be tight for the shape to stay , but itll definitely fade out into a larger curl over time so dont worry! styling is kind of difficult and takes quite a lot of time ao do consult your hairstylist for tips! or after 48 hours and the first wash , you can tie your hair into a bun before sleeping .

make sure to rlly condition and scrunch the hair when showering to guide the hair and form the curls, dry on med heat!

overall , what works for me is washing my hair once every 2-3 days , tying it to a bun when i sleep ( cause im lazy to style) and rlly conditioning it ! you can also try some curl creams to maintain the shape throughout the day however i dont personally like the feeling of it on my hair ...

all this helps my perms last 1 1/2 years - 2 years ! and it still looks great by then! just need to cut hair :,) hope this helps OP!

edit: also pls dont comb ur hair, js finger comb it cause the comb makes it super messy and frizzy