This one is actually pretty hard to miss. The achievement is unlocked when you complete the secondary objective "?" in the first chapter. To complete it just follow the the yellow exclamation mark on your radar and walk into the glitch. When teleported into a new area you can turn around and walk back through the same glitch you came through and you will unlock the achivement.
http://images.akamai.steamusercontent.com/ugc/64099450519716...Credit to "^6Tallguy" on steam for this guide
Mission 1 - Area1