what steps would you recommend i take to prepare to enter this field?

Hello Artadius, your on the right track by knowing already what you want to do. I would recommend you read up on Job Corps on their webpage to pick which location you'd like to be put in and make sure they offer the field you want at that location, because different centers have different jobs they train for. Their webpage will tell you which careers are at each location. Also you can get prepared by watching youtube videos on for example how to lay bricks. Mostly don't worry too much about going into the JobCorps already knowing everything, remember that's why your going there, to learn and likely everyone else there will have as much experience as you do now.