How does fusing work?

As in what is the main point of fusing equipment?

The point of fusing is to combine 2 items to make a new item.
It's sort of like redemption for below average equips.

how is the fused item determined? is it dependent on what you fuse? And if so, in what way

you scroll two pacs, they come 0 attack 0 slots, that's useless, so you use fusing to get a brand new average pac, simple as that.

put two of the same item to fuse, you get a third that is the same thing.

And the new item has a chance to come out Unidentified.