To pull up the powers you have hit the right bumper from there you can access your teammates powers as well as yours, your powers come up as ammo. Here I will break down what power or ammo to use:
Enemies with shields-Use a teammate with Overload you can also select Disruptor ammo for your weapons as it is good against shields if you don’t have a teammate with Overload.
Enemies with Armor-Use teammates Incinerate Power or Incendiary ammo for your guns, you also can recruit a teammate who has an Inferno grenade power
Enemies with Barrier-Use teammates that have Warp or use Warp Ammo for your guns
This is just a basic rundown of what you can use I can go more in depth just shoot me a message when you’re online and I can explain further.
EDIT:Yes you can combine your power with your teammates as well.
