How To Play Co-op

At the bottom right of your main screen, TAP on the Co-op icon located between the SHOP and TEAM icons. 
Once you enter the Co-Op area of the game, you will have the option to choose whether you want to try doing a 4 player or a 2 player mission run.
After choosing the number of players that can participate in the mission, you will be directed to the difficulty screen. The number of stars determines the difficulty of a quest.
After the difficulty of the mission has been set, you will be given an option if you want to play with a RANDOM PARTY or with your GUILDMATES.
After selecting your party option, you will be directed to the waiting screen where you will be asked to wait for the party to be completed. Once all party slots has been occupied, you may TAP on the START button at the bottom part of the screen.