Singing -- How to tell if you're singing with diaphragm?

Well...basically first of all you must not eat too much also dairy products. Clear your mucus, make a lemon juice. Mix the lemon juice with warm water and drink it about 20min. After you're done you can feel that your throat is clear and refresh. Now, sit infront of your mirror on a chair. Slowly, breathe inside and close your mouth. Your shoulder should not move only your stomach expand when you inhale and try to sing! Keep practising if it's not perfect :D. So, good luck! Hope I help it. Thanks