Chapter one starts off with Jesse, Reuben and Axel/Olivia in the nether travelling in a minecart.
After a quick conversational choice a ghast will attack and knock you out of the minecart, once you land you will have a quick right QTE to move you behind a group of nether, you will then have to choose from a bow/sword to fight with. (I choose sword)
Another movement QTE and its time to fight, when the ghast attacks use
to deflect its shots back at it, do this a few times to kill it. (Took two deflects for me)
You'll all then get back in the minecart and carry on your way. Once you make your way to the nether portal for Redstonia/Boom town you will travel through the portal and have a cutscene to watch. Once this ends you will end the chapter and the achievement will be yours.
Note: This isn't unlocking for everyone, if it doesn't try rewinding the episode/making a new save to replay the chapter. It appears if you're going for Ellegaard this will be bugged, going for Magnus will be ok