Things to Carry
A water bottle - You feel dehydrated after 3-4 hours surf session, so it's safe to carry a water bottle or some energy drink with you to feel energetic.
Rash guard - It's mandatory to carry a full body rash guard for beginners as you are going to fall a lot and get some bruises on your body. So don't forget to pay a visit to Decathlon before you go for surf.
Sunscreen - Since you will be exposing yourself to the Sun for longer, it's good to carry a good quality sunscreen with you.
Waterproof case for your cameras and phone - If you are interested in photography/ videography at the beach, it's safe to use a waterproof case for your phone or cameras.
Some Tips Before You Go For Surfing
You are going to fall off your board. A lot. Get used to it. It is all part of the fun at the start of your learning curve.
Another thing to remember when you are in the water is to keep hold of your board at all times. You should have an ankle strap or leash but do your best not to let go when you fall or when you are paddling out.
Surfing is very demanding on the body as well. Make sure your basic fitness is up to it. You need to have a strong chest and arms to paddle out. So, get fit and you will go a long way to making sure you are safe.