It says somewhere on here that you can train your pet. I have a Trainer Invite in my inventory, but I have no idea what to do with it. How do I train my pet, and what does it cost to do so?

You would only be able to use that invite with a building called the Inn. Instead, finding blueprints for the Ridinghall and then constructing it would most likely be easier. With it, you can train up to three pets at a time. Once it is fully operational, go to the page of the pet you want to train and the option should be on his/her page. The cost depends on how much XP the pet needs to increace a level.

I find it's much easier and cheaper to fight on the arena in manual mode. Each battle won gives you XP.

Oh. Thanks for clearing that up. I've also been seeing things about quests. Not the daily quests, but the ones that get names like the Dream Gate quest. How do I do those?