First, I must say that procedural generation is not a very beginner friendly technique, but in no way I want to discourage you, quite the opposite, but since the ideas behind it are not trivial, you can find it hard in the beginning and lose the interest. Because of that, I would first suggest you try to create something the way you want (your desert with the rooms) in a static way, and later migrate to a procedurally generated way.
That said, I would suggest you read this: https://craiky.github.io/tutorial/ it's a tutorial about procedural generation, but it teaches it in a nice way for someone that's learning programming (and it's uses javascript, which is a plus).
Later, when you feel more comfortable with javascript and programming, I would recommend you to check Roguebasin(it's very focused on Roguelikes but it has very nice articles on generating procedural maps and other techniques to develop these kind of games, that can be used in many different games).
Good luck.