Pressing the Assault

To finish this quest, click on the third tab at the bottom of your command map window, and select a zone.

The part that directs your followers on quests is the first tab, and a list of your followers is the second ... it didn't occur to me there was a third tab at first. By the way, your Command Map might have a slightly different name - in the Mage hall, it is called a "Scouting Map".

This is just a "helping" bread crumb quest to guide you into the questing zones. If you already completed leveling you can simply abandon it. It has no followup. If you abandoned it, but already explored several zones, it won't be offered again. This is supposed to be a quest for new players and help them get into the questing zones. Once you started questing in several zones, there is no need to guide you to them. I am actually amazed at this smart quest design :)

If you have already started the next area quest chain before finishing this pre-quest, you can accept yet another area starting quest at your command table, and then abandon it (and then take it again when you wish to actually do quests there).
Or, if you have accepted all the area starting quests at once, but haven't yet started doing them, you can abandon one of those quests and then accept it again.
This way you won't have the "Pressing the Assault" quest hanging unfinished in the background.