Inventory

Hello.
I wanna make a game in which you could collect items, use different kinds of weapons. Adding items seems pretty easy. I also found community created inventory. But, I can't seem to put these two together. Any item added to the game is not visible in the inventory. So, no matter how I tweak existing items, they never appear in the inventory or equipment slots.
For example, I want to add a sword and a crossbow as weapons, I want them both being visible in the inventory and I want players to be able to switch which one they want to use. However, I can't find any information of how to do it.