There is a kind of tutorial if you talk to the goddess and select help. It explains things like interacting with structures. There are also some tips in the description of the game, but I get that it's not much. If you have questions, I can answer them and help you along at least.
To craft in the inventory, right click with an ingredient to deposit it into the crafting box (left click to remove an ingredient). The crafting box will after a short time output the result, and you can pick it up with shift left click or shift right click. Structures work the same.