To be fair, creating such a project requires the stitching together of all the little parts you mentioned (health bar, inventory, etc.) and more (using the magicam plugin for example). You'll have to learn what the events are doing and absorb a lot of tutorials, capx's, and topics to get a feel for things.
Try to start small with implementation: moving the player, attacking, and some enemies, and so on. A recent topic I made covered how to make enemies randomly move around, but they don't check for solids, which limits their effectiveness (that's something you'd have to figure out; I haven't returned to the project yet).