How to organize squads in GVG

I used to be in a guild where when we did the guild versus guild, the teamleader put the team list in a certain order. Everyone was thrown in the same team but each row had a tank, a DPS and a healer. Row 1 was also set as squad 1, row 2 as squads 2,... I have tried to figure it out myself but have not been able to. Does anyone else know how to do this?