First at one point we all feel unhappy with our work but that will make improving all the more rewarding. It’s okay to look like a beginner if you are because when you get better people will notice and take that into account. If you are really worried watch tutorials by Mary D Sava, Joseph Evans, Episode Notes, Episode tv and Bronte. That is how I learned and don’t be afraid to ask people to be beta readers to get feedback on your work.
And as for overlays you can watch tutorials for Joseph Evans and Episode Notes.
But the basics are to add one to a scene you can use one of two ways.
INT. BACKGROUND with OVERLAY
or if you want to add it in the middle of scenes use
@overlay OVERLAYNAME create
@overlay OVERLAYNAME opacity 1
and you just use the code in the box below the previewer (it’s just like spot directing a character)