At the top of the each forum section there are sticky threads. Giving them a quick read will help you a lot. They are sticky because we need to keep coming back to them and don't want to hunt them down.
Read the labyrinth guide there. That is the only source of Spirit plans and you will need them. I will say this, if you are on a server that has a lot of experienced players with high power levels then I would wait a few days until the new servers open and start on one of them. It will allow you to compete on even ground rather than try to play catch up. Also look at the story and lore page for formations to bosses. You will see some heroes that are on most of the formations. Those are the ones you want to recruit and spend resources on. Good luck.