Inventory help

I need help figure out how to make a inventory like this.

Explain - the inventory is focused on a wheel like inventory. each item takes up space in the wheel. and the last item on the wheel is the ammo, witch is just the same as this but with ammo. i really need some one to help me figure out how i can make this. I'm confused and i knew that someone said to use UI system, but still im confused on how i can make it look like this and code it.