Welcome to the Zone.
Not sure of a lingo FAQ page. There are plenty of long term members you can ask or shoot a PM to Mike the site owner/host with the most here at the Trading Card Zone for more info.
Lets get box breaks out of the way. On the basic level what happens is the break host makes a post about the break and asks for people to sign up and pick a team. Usually the goal is to have 15 people (16 for NFL breaks) participating in the break with their chosen team and then they get a second team either by randomization or quick draft. Many of the breaks around here are ongoing monthly breaks that you will have to check with the break host and request to be put on the wait list for your team, or when a slot opens up.
Other sales are usually in the buy/sell/trade sections divided by sport. Offers are posted and you respond to the post and or PM the seller for more info, details.
I hope I answered some of your questions. I'm sure other members can come by and give you more info, or better details on some of them.