I don't follow this part, still. Do you mean computer screen / phone screen behind my finger which I would try to look at?

I can switch between my left and right eye when I concentrate, but I can't see both at once. I can try to rapidly switch from left to right to back, but it takes a lot of effort, and it's never the same image at once?

My right eye is dominant, I can switch to left eye if I focus hard, but I can't merge both or can I?

Edit:

I tried putting a paper between my eyes, so right eye would only see right part and left eye only left, am I supposed to see the whole image at once then combining the inputs from both eyes at the same time? Because I can only see left or right, as if my other eye was closed, even though it's not.

I'm wondering if something is wrong with me.