Help with PS express premium / selection tool

[LORENE6C19]

I am using PS EXpress premium on Ios Ipad. Photo loaded, I go to adjustments: select tool; drag across photo to select subject that I want to remove from background. This object highlights red and a new layer called selection one is added. (There were previously three layers; full/subject/background) OK now I have the object that I want to remove from the background highlighted in red: what do I do to execute this???? I have clicked everything on the page to no avail. If I save it here at this point it just saved as the same photo. I don't know what I did one time, but it saved as you see it here with the red.