You appear in the antechamber, a lobby where you can buff and prepare for the fight, with the option to enter via the Legion Portal or exit via the Legion Tome.Your alliance enters their own separate instance of the Maquette, similar to Nyzul Isle.
Trade the Legion Pass to the nearby Legion Tome to enter.When your alliance of 18 or 36 is ready, speak to Mayuyu at (J-5) in Rolanberry Fields to select the section and obtain a Legion Pass.Entry is granted by obtaining a Legion tome page from Saarlan (J-5) in Rolanberry Fields.
There are five sections: "Hall of Skies," "Hall of Earth," "Hall of Winds," "Hall of Clouds." & "Hall of Mul".Requirements: Main job of level 75 or above and Three to thirty-six participants.This is the area to participate in Legion.Rolanberry Fields: via Legion Tome in the Lobby.