The basic idea of minecraft is a sandbox game where you can build what you like and do what you like. However is you have difficulty on easy or harder during night and in darj places monsters such as: Zombies, creepers, skeletons and spiders will spawn. You dig resources to collect them and right click to place them. If you open your inventory (E) then there is a craft section where you can turn your materials into other materials. So if you cut down a tree and get 2 wood blocks if you put them in the craft section you get 8 wooden planks