OK you're doing well so far. Keep doing push ups on your knees. Than after a while begin slowly to lift up your knees. It might not be easy, but keep trying eventually your whole body will be in sync with your hands and knees. Good luck and may god bless you.
You can also check out some of my workouts they may help.
Knee push ups are a good beginning. But you can also try plank to build a little bit your core and shoulders.
A good workout to work differently is the dips. It will give strenght in your arms. After that you can also lay down on the floor and push. Back to the floor and rest and push etc...
I agree with Herel. Planks are a great way to strengthen your core in a way that will make pushups easier. Try doing full or elbow planks at least once a day. Twice a day if you really want to see results. I recommend once in the morning and once in the evening. I started doing planks every day a little more than a week ago and I've noticed already that my pushups have improved a lot.