How does the GUI work?

I can't make sense of how to set up the conditions.
I've tried to hook up with both red and green wire to both sides of the splitter with read and set each condition on the splitter with desired item(s) and amount.

From what I can tell it ignores conditions and only able to filter one item at a time by how I'd filter a normal splitter. Only benefit I can see with this is that it prevent the belts from backing up thus saving me from using one extra splitter which is a plus

In alt-view the splitter only shows the first item. The mod thumbnail is a little paint magic, not in-game representation. There is certainly some points of improvement to make the sushi splitter (behaviour) more distinctive.
I'll try to make a mod page on the forums some, so everybody can share screenshots and bug info.

When iron, copper and steel circuit conditions are set on a positive value (red or green) and the sushi splitter has an output (left or right) and the sushi splitter has 'set filter' checked. Then it should send those three items to the designated output until it is full. If it doesn't that certainly sounds like a bug to fix.

Screenshots to clarify issues, bugs and general questions can now be posted on the forum
https://forums.factorio.com/viewtopic.php?t=131863

Awryt, ta

I think it was a user error that made me confused at first

I thought the input and output gui was meant for to set the splitter for what to take in on which lane and output the stuff on said lane in the output section. but today I realized I should use combinators and signalling to control what get filtered (I am green when it comes to circuit)

Once I figured out how to use it more properly I love this more and more. Keep it up but I'd like to see some use case examples for the gui and such though, when you have the time for setting something like that up but that will come in time I'm sure now that you have that forum up and running :=)