How does Ranked Teams' ladder work?

I created a team with two friends just to play Rankeds 3v3 for fun and what not, completely unexperienced on this. After getting placed in S4, we reached 100 points and got placed into S2 without any promos. I might sound like a noob, but I really don't know if this is intended. I've heard about people jumping two divisions, no biggie on that, but I didn't know that there weren't promos in Ranked Reams. Can someone provide me more information or some links containing help about this ladder system?