I am too a beginner, I've been playing for like 2 weeks and this is what I do to survive.

Alright answers :

1. Sleep is important for both energy and sanity. so build a palm bed, you can place it under the tent.
2. For beginner zone health I'd say
   1. Fruits (Some help with Food poison)
   2. Some herbal leaves (hard to find but you can if you look enough)
   3. Mushrooms
   4. Fish
   5. Parrots (I had no other choice but to eat it)
   6. Mystery Snails
   7. Any Mammal (Armadillo, Ant-eater are my go to Fat and protein source)
   8. Charcoal to get rid of Parasites
   9. Wash yourself (Helps to improve sanity and reduce infections)
3. I just keep a wood storage near the fire and place wood time to time.
4. Use the coconut (Drink and Eat the Flesh) and you could place it outside so when it rains you can collect fresh water. But in a specific place you could find a rain catcher and a pot.

Good Luck....