Help with masking in premiere pro

[Jesse5EA1]

Please help guys/gals. I am new to editing and trying to mask my first video sequence. After going through several Youtube tutorials it seems as though my software does not do the same thing as the tutorials. 

Ive cut the clip and am using a tree to reveal new clip. Ive outlined the reveal with the blue dots but it never turns black? I realize im suppose to go frame by frame dragging this black mask but cant seem to make it work. Super frustrating! Please help. What am i doing wrong?

[John V Knowles]

It's kinda hard to follow what your issue is; we really need to see what you're attempting to advise you on what's wrong. Can you post screenshots or a screen video capture?

JVK

[Phillip Harvey]

We may need to see more, as John suggested. The one thing that comes to mind is: are you closing the mask? You have to complete the entire mask shape, joining the last point with the first point, before the mask will work.