Clarification for the Crystal Exchange event

So from the current crystal exchange event, it seems like you only get around 400 gems max here. But the info on the bottom left corner says something more (or so I thought)

"Once the ticket registration period ends, the period to claim rewards will begin."

What did this quote mean? Is there a part two to this crystal exchange event? I'm a returning player and I have absolutely no idea what's going on. Though the free T3 units the game has given me are pretty nice. Maybe I'll consider taking a hiatus from playing this game after the anniversary lol