Going On Beach vacation with 6 month old

My fiancé & I are getting married in a couple weeks & a family member of his has offered to buy us a honey moon that we weren’t going to take for ourselves because of the money.

We are going to take our 6 month old son with us - but I am lost on what some essentials are. I am losing sleep! I know sunscreen & a sun hat, but I just don’t know what to bring to make sure this experience is pleasant for all of us.

It will be a resort & a beach vacay since we just need some time to relax & unwind, we would normally going on exploring vacations.

What do you all recommend is a must for beach vacations with babies? How’d you even take a baby on a plane? Help!