How do I make my baby sleep on his own (without carrying or drinking milk to sleep) ?

I have a problem putting my 9 mth old son to sleep. I've been trying to let my mom know that I want him to learn how to sleep on his own but she keeps on carrying him to sleep. Now I've enough of it and put a stop to it. But now that he's already 9 mths old how do I let him learn from scratch to sleep on his own? (As in playing till he's tired and just lie down and sleep)