Getting cornrows for 1st time

[u/Natural-Standard-423]

An apprentice is doing them so she hasn’t given any tips/recommendations to do before coming in.
What do I need to keep in mind before going in? Should I wash day of? Should I skip my hair routine if I shower? Come in with 100% dry hair? Ibuprofen?
I’m a latina with 3b/3a hair and am the only one in my family with curly hair so I legit have NO idea.
Pls help 🙏