couple changes since LK.
Beacon of light on tank. That gives him half heals on most, plus full on holy light. (used to be full on all)
Also we don't do big huge mana pools like we did in LK. The world changed. Spirit is your friend now for mana. Instead of the big pool, it's more 'same pool as everyone, but how fast does it refill?'
In LK holy light was big slow expensive, flash was fast small and cheap. This is no longer true.
Divine light is big slow mid mana. Flash is fast medium sized, and mana expensive.
Holy light is small sized, medium speed, low mana.
Holy shock is still holy shock. Use it.
Holy radiance. The awesomeness of this spell scales upward depending on size of the group. In LFR it's 25 which means you could really just spam this spell the whole time and do well. Generates holy power.
Light of dawn is your Care bear Stare. Shines a happy light in front of you that heals people. Uses holy power.
So...for raid heals...Holy radiance with some holy shocks thrown in for pepper. And light of dawn to use holy power. That sentence alone and you'll be OK in lfr.
But, to be a little more useful: cleanse is your dispell. It has a Cooldown now, but it's VERY important for some fights. Divine Light if tank is taking damage. Flash of Light if the tank is getting his butt handed to him and you need to do some healing quickquick. Holy light if you get bored and want spot healing (really holy light is great in 5 mans, but I never really touch it in raids. It's a good..."small heal on dps that also hits tank" spell, but in LFR there are lots of dps...Holy radiance will give you more bang for your buck.
You can also use holy power to single heal tank (word of glory/eternal flame, depending on your talents)
That's the basics. There IS more. Stat priorities, situational tactics, mana control, Sacred shield vs eternal flame... There's some other really great places to find that information, including the stickies atop this forum, and I strongly recommend looking into it when you get comfortable enough. But for day 1...this should do.
Also...don't panic. Healing LFR is super easy. You'll be fine.
Edited by Jaxzer on 9/14/2013 9:10 PM PDT