I am working on a JetBlue poster as the final exam project for my photoshop course. I am almost half way through the assignment and I have a masked layer of a beach with sea and a lifeguard post and a palm tree. There's technically more to the layer than that originally but I masked that out as this is only supposed to be one part of the final image.
I have tried adjusting brightness, contrast, etc, but it always makes a new layer that includes everything. I want to use an identical or same mask for the contrast, levels, etc, as my Miami Beach layer. How do I do that?
The image so far is attached.