my face time settin will only recognize my email account but I also want it to use my iphone number

I have a Macbook Air, an ipad mini and iphone4

somehow I changed my account ?? not sure how- so that now I can only use my email account as a way to face time

I think this was because I used my macbook??

I would prefer to be able to use my iphone number and have that sync with my ipad

what do I need to do to change back to this