Fate offers three methods for teamwork: combining the same skill from multiple characters on a single roll, stacking free invokes by creating advantages to set up a team member for success, and invoking aspects on an ally’s behalf.

When you combine skills, figure out who has the highest level in the skill among the participants. Each other participant who has at least Average (+1) in that skill adds a +1 to the highest person’s skill level. Providing support like this uses your action. Supporters face the same costs and consequences as the person making the roll. The maximum total bonus a team may provide this way is equal to the highest person’s skill level.

Otherwise, you can create an advantage on your turn and let an ally use the free invokes when it makes sense that they can. Outside of your turn, you may invoke an aspect to add a bonus to someone else’s roll.