Hello , Could someone give me tutorial of how to make an inventory + hotbar or hitbar . and if not ask much about crafiting systems
The link Enerynone gave is a very good start and a very good intro to things like Structs. It does brush over some things. I just wanted to give you a heads up that inventory systems and crafting systems are not entry level topics. I have created my own before and know from experience they can take some time to polish and add all the functionality you would expect, like dragging, dropping, equipping, using, stacking, or splitting stacks, etc.
If you do have a solid understanding of blueprints, arrays, structs, loops, UMG, etc. and feel you are ready then my advice is decide exactly what you want from the system before starting. For example, a Dark Souls inventory is very different from a Witcher 3 inventory, or a Final Fantasy inventory.
Good luck.