As well as having a look through the various tutorials (I messaged you with a selection of links a little while back) I think you may benefit from playing the published free Choice of Games games which will give you an idea of the scope and structure of these games. Here’s a list of the ones that are currently available for free:
Revenue from these games varies a huge amount but you may be running before you can walk - focus on figuring out what you want to make before worrying about how much money you might get from it.