Some quests reward players with crafting recipes, and we also have a chance to get recipes from gathering resources (Fishing at the start of your day is a great way to find a recipe) around the island. Donating items to Tallow's cabinet also gives cooking/crafting recipes as rewards. These recipes will unlock new items to craft or cook.
To learn a recipe, simply access your inventory, select the recipe you'd like to learn, and hit the "learn recipe" button from the action list. Once done, give the crafting machine a visit to check the cool stuff you may create or the cooking station for delightful food you may cook.