Did you try lowering the graphic settings?
There is an instructions menu with some help. Look at the crafting menu, building menu and inventory to see what you can do with the collected items. Like you can craft a coconut into two coconut halves which you can eat which reduces some hunger and thirst. You can craft palm leaves into rope, together with collected stones and sticks from the trees you can make a shovel. With that you can dig sand and build a bed for example. Out of eaten (empty) coconut halves and other items you can make a water distiller to turn collected seawater into drinkable water. And so on.