Healing in BC Dungeons

Hi all! I've been looking for more information on healing in dungeons for BC content as a Shaman. All of the guides I've found are focused on raiding content. And that's great, but I'm new to playing a healer and would like to do smaller content first (plus I'd like to gear up a little).

Some things I've noticed: I go OOM really quickly, basically every single pull, even with Water Shield and Mana Totem. I suspect that some of this is just not having appropriate healing gear, but I'd like to get that clarified ahead of time. I know downranking is a thing, but its not really clear how much I should be using lower rank heals.

I've also noticed that totems cost a lot of mana. Should I be deploying all my totems for every pull? Currently I have my macro set to do Fire Nova, Mana, Strength of Earth, and Windfury. Clearly I want to help the group with totems, but if it depletes a big chunk of mana at the start of each trash mob pull then that increases the risk of me going OOM.

Is there a way to deploy all your totems at once? I know that was a thing in Wrath with a specific widget tool that does it. I just wanted to check to see if I'm missing something. Currently I have a macro that I have to press a couple of times to deploy them all.

What do I do if we accidentally pull too much? I've had trouble dealing with pulling multiple packs (or getting roaming mobs added). I've been defaulting to blowing my Mana Tide cooldown and spamming Chain Heals. But it often feels like that's not enough, especially since it pulls aggro on me.

So basically: what rank heals should I be using, what's up with mana, and does anyone have any tips?