What to do at Couples Negril--1st timers in May

May will be our 1st trip to Jamaica and Couples. We are staying at CN.
What should we definately do or not do.
Looking forward to the beach. It looks wonderful and everyones threads have been so helpful and love seeing all the pictures. We aren't planning on going to AN beach.
Looking forward to Cat cruise.
Can you wear shorts to dinner any nights or are all dress up. We are kinda layed back casual especially on vacation.
Sooooooo excited!!!!!!!!!!!!!!!!!
Thanks