Could someone help me make a custom inventory with custom tools?

guys i am not a great at scripting my self however i would really like to know of how to make a custom inventory with about 20 slots. if any of you could make one for me that had some instructions i would be very grateful. maybe you could make a model and then send me a link for it that would be amazing I would also pay 100 Robux for it if you are first to make a good one ;D