-Go to Arcade mode via the game's main menu or in-game menu
-Play Solo & Co-Op
-Category --> Featured
You can choose any of the featured maps/modes (currently at the game's launch there are 8, all created by Ubisoft). As the achievement description states, you do have to successfully complete the map, so failure doesn't count. Playing the same map multiple times DOES count toward this achievement.
The Journey maps seems to be the easiest, since they're basically getting from point A to point B, and one of them (Upside Down) doesn't even have any enemies. The XP you get for those is very low compared to the others that involve killing a lot of enemies, however.