Pro-AM is a new category under the new 'World of CHEL' game mode.
Here, you play 3v3 style pond hockey. The difficulty is preset and seems to be the same throughout all the World of Chel modes. It's quite easy to use your right stick 'left-right-left-up' or 'right-left-right-up' while gliding, to score deke goals. Regular shots are pretty straight forward, check out the Training Camp Tutorials if you're having trouble!
Games are 3, 2-minute periods after which you gain 300 xp for your character which is pretty generous. After you score a goal, you can even just skate around and hog the puck to eat the clock!