You have to craft syringes that give you special abilities. The recipes are unlocked as you play and you will get a prompt when they do. You have to have the right amount of the various plants in your inventory in order to be able to make them. You can assign up to 2 types of syringes to your left or down D-pad for quick access. In the crafting menu, under syringes, you can highlight a category, like hunting, or combat, to see which recipes you have unlocked, and what ingredients are needed.