Making items is easy.
You just put up a list of ingredients. (e.g)
Give an action you did in order to synthesise the item.
And then state what you made.
Now obviously there's some rules to it.
1. Anything you make is made of the items you put in. For example. If you try to make a sword out of twigs and leaves, that's fine, but it's still a sword made out of twigs and leaves.
2. If you want your items to have magical abilities you'll need magical items. No flame swords without flame items for instance.
3. Make whatever you want as an item. But remember these things must be small enough to carry.
Note: Yes I do see all the flaws in this little system. It'll become more advanced later, but until then everyone have fun making items.