Team play is one of the essential things you need to focus on during the game. In the initial stages, you will only have the Gem Grab mode unlocked. Rest you have to unlock. As the battles are 3v3, one of the players should be the gem collector, others should be playing as defense, and the last one should be playing offense who has to attack the opponents. Gem Grab is all about collecting gems. The team which collects ten gems first wins the battle.
Do note that if your gem collector dies, all of your gem collection will be lost and acquired by the opponent teams. This is the fundamental reason your gem collector needs to be safe, the attacker should drag the opponents away, and the defensive player should stay near the collector. Staying near to the collector will give you an opportunity of grabbing all the gems if your collector dies. In this game, you cannot win a match on your own. Team play is significant, not only in this mode but also in other modes of the game.