Need quick help working with masks

So here using cross only the masked area is visible

But when i switch to alpha over it just shows the original video when I want to make the black part transparrent to show the video underneath it

Can’t find any simmilar tutorials or info to what i am trying to do.

Have you tried overdrop?

How about hiding the layers below the adjustment layer?

I’ve never used adjustment layers for masks before, so I’m not sure. Typically I’ve just applied the mask as a modifier to a metastrip, but even then I rarely have to mask all my strips (which is what adjustment layers do). I’d normally only need to mask 1.