If you have iphone/android download the app "You are your own Gym." Its $0.99 on Android and well worth it. It has a database of ~200 bodyweight exercises ranging from beginner to advanced. It shows you multiple pictures during each exercise so you can see the correct form. There is a companion app with videos. There is also a book with the same title if you check amazon.
For shoulders and progressing to a handstand pushup start in this position