How do you heal as Holy?

So I did it, I bought my dual spec and specced holy. My spec is probably not very good. Newguy. I jumped in a group to do H Toc to test it out since its got some good aoe damage to deal with. Well we went through with no wipes but I was running around like a chicken with my head cut off. What do I do, I have been disc for like a year and its so easy to just pop bubbles, PoM and penance and that's like all I do. With Holy I was just throwing everything out there CoH, Greater Heals, free flashes, PoH, PoM, and binding if I was taking damage. I was totally confused. Any tips would be appreciated