In Yu-Gi-Oh 5Ds Stardust Acclerator how do you find a tag partner for the tag contest

In Story Mode, you can only have partners who are the individuals of another Tag Team (and Yusei or Akiza). After beating them 10 times (not in a Tag Duel but a regular duel), you'll be able to Tag Duel with them in Story Mode (and World Championship Mode).