Co-op is not two MyPLAYERs. Your friend controls Trace Miller, a custom NPC Running Mate you meet in the G League. Trace stays on your roster for the rest of the career, story quests force Running Mate plays, and a lot of people just want to know how to unlock invites, finish the D-pad quests, and pick a template that does not feel like dead weight.

1What Co-Op Actually Is

2Unlock Trace and Invite

3Running Mate Plays (the quest everyone gets stuck on)

G League and early NBA games give objectives like: run plays with Trace on ball, you on ball, and neither on ball. Press Up on the D-pad to open the Running Mate mini-menu (about 4 actions: PnR, floppy, iso-style, and more).

Easy loop: Pass to Trace, call iso, call the ball back. Or run pick-and-rolls the whole game. These plays also feed Running Mate chemistry and extra skills over time.

4Key Decision: Which of the 9 Templates

Pick the one that fills the hole on your build, because Trace takes a real roster spot and you cannot drop him. You cannot change the template later in a way players have found. Decide before you confirm.

You are a wing or SF scorer
Giannis template
Boards, rim protection, PnR and PnP, enough shooting for kick-outs. Multiple posts call this the least backpack option.
You are a big or C
Curry or Mitchell template
So you have a shooter and spacer next to your rim presence.
You are a scoring guard
Jokic or Cade template
For passing and size. Avoid two smalls on the floor at once.
You are already a tiny guard
Avoid locking another tiny guard
Unless you want two smalls. One poster picked Curry and felt stuck in story.

Fight Demonstration

Common Mistakes to Avoid