If you're after completing this achievement ASAP, open the spoiler. If you are after enjoying the story without spoiler, just continue playing as you would and this will eventually unlock.
Things might be a little different for you as choices affect how the story goes.
*** Spoiler - click to reveal ***
Either let the Ocelots charge or talk to the admin. You'll have a discussion with the admin afterwards. He'll start destroying Beacontown by placing a lot of bedrock in the sky. Rush to the portal and perform the correct QTE when prompted to do so. Move forward over the bridge with Petra and Jack. Use the grid. You'll have to make the blocks 4, 5 and then 1 high. (So remove the top 2 blocks on the left, the top one in the center and all but 1 on the right) Then back out and open the chest. Place the poisoned potato on the item frame. You'll "meet" Fred and he will give you the Golden Gauntlet. Say "Yes" when you get 2 choices.