Union apprenticeship sign-ups near Milwaukee

I heard of an apprenticeship with paid on-the-job training for people changing careers. Thank you in advance. Classes are in the evening and work is during the day. What do you wish you had known?

The aptitude test was mostly maths and reading a diagram. Free practice tests online were enough for me.

Bring your transcripts and any proof of work history. They asked for both in the interview.