You’ll need to agree on what roles each of you will play on the team before facing online opponents. To add friends to your team, simply ensure that you set your size to either 2v2 or 3vs3 depending on how any friends you have in tow. Superstar KO will see you and up to two friends building a team with a handful of superstars and a celebrity coach and then playing quick 11-on-11 games with OT rules.
Superstar KO and The Yard are similar modes in that they both allow you to team up with buddies to play games on the same team, but they also have their subtle differences.