so look here.
at your left hand is your party and in the right your enemy.
from left to right you have your White unit (uses white orbs), black unit (uses black orbs) Gold unit (uses golden orbs) below you have your orbs, every time you use it they move to the right so you can fill your board with new orbs.
to the sides of the orbs are the assist units, they give you a passive or active skill depending on the unit, you can use one from your collection and one from a member of your guild
each unit has 3 skills that you can activate by using the orbs, 1,2 or 4 depending on what you want to do. (some new units have 3 or 6 orbs instead of 2 or 4)
in the enemy health bar you can see a number, that shows you in how many turns it will attack.
the best part of the game is making teams and discovering good sinergies with your units.