tracking window options

hello
I am trying to learn how to create some useful windows "masks" on this shot I am posting here by pictures
my problem is that i don't know how to do 2 things:

one is to create a window shape with a free pen sort of like in AE.

and the other is that iI don't know how to enable a window so that it will work on the image not from the exact beginning of the cut but for example as in this pictures that I posted, let's say I need the window to softly appear at around pic 3
when the guy standing gets closer to the camera.

is there any sort of gradient opacity control in the grades ?
thankyou

hello
I am trying to learn how to create some useful windows "masks" on this shot I am posting here by pictures
my problem is that i don't know how to do 2 things:

one is to create a window shape with a free pen sort of like in AE.

and the other is that iI don't know how to enable a window so that it will work on the image not from the exact beginning of the cut but for example as in this pictures that I posted, let's say I need the window to softly appear at around pic 3
when the guy standing gets closer to the camera.

is there any sort of gradient opacity control in the grades ?
thankyou

I beg you of reading the corresponding pages of the manual. It is beautifully written by a professional colorist in a language that one can easily follow. All of your questions are covered in full

^^^^^^^

Yes, read the manual....