Watch the cutscene, in which you will be given a Supplies Package.
To complete the mission, you need to take the Supplies Package to one of the Assault staging points; any one of the five staging points will do. Eventually you will want to go to all of them; much like supply quests, you can only use the Chamber of Passage to get to a staging point after you've used the Runic Portal at that staging point.
You only need to do one of the staging points to complete mission 2.
Take Aht Urhgan Whitegate exit to Wajaom Woodlands. If besieged is going on you can take a tunnel next to the bottom of the stairs at H-10. It is the little tunnel on the left side of the south square where the ship from Mhaura docks.
Alternatively, you can use the Survival Book to teleport into Wajaom Woodlands.
Travel west, then south until E-12 and enter Mamook.
Wind your way roughly south and west until F-10 and enter Bhaflau Thickets. Poroggos are true hearing, take care when crossing their paths.
You will be on the southern half of the second map. Head south to H-11.
Enter Imperial Compound through the Heavy Iron Gate.