It’s unfortunate that your screen shots don’t show the left and right hand panels in the builder. Those panels provide additional context that helps us to interpret what is going on.
But anyway, if I’m understanding correctly, it looks like you are trying to use a Table Collection as a form? If that’s true, that certainly explains why you are struggling to get things working as you would like. That’s not the intended purpose of a collection, and so it’s like trying to insert a square block in a round hole - it won’t work.
A custom form is something completely different. Have a read through the below thread: