The reason I believe the questbook doesn't mention it is because it is well documented in both NEI and the Lexica Botania how to get the mana pool. As for iron, you need to follow the quests in the "What the World is Made Of" Questline. It's part of the quests that use the first infusion stone. If you're ever wondering about resources, they're either in that questline or "What the World is Built From" for your more end-game resources like diamonds and certus quartz.
NEI is utterly confusing though to someone who has no idea what the mods are because the recipes for mod crafting blocks (I.E Mana Pool) are confusing, I hardly know half the names of the mods in this pack. I checked the recipe for the Mana Pool and the picture you get doesn't really look like you should *throw* the item in the Diluted Mana Pool. It also doesn't say in the Lexica Botania that you *throw* items into the Diluted/Regular Mana Pools, as far as I could tell.
Thanks for the quest tip though, mind telling me around where that quest comes up? Is it in the second "chapter" or still in the first?