I need to sing from my diaphragm!?

I only sing with my throat and I have absolutely no idea how to sing from my diaphragm! do you have any tips? i've watched videos and read other answers but there is nothing that has helped me! and i really don't have time to take voice lessons. I'm also in the play Annie right now, casted as an orphan so I need help belting, but first I need to learn to sing from my diaphragm. Thanks so much!