Union apprenticeship sign-ups near Boise - what worked for you?

I heard of an apprenticeship with paid on-the-job training for people changing careers. Thank you in advance. Applications close in 16 weeks. What do you wish you had known?

You earn while you learn, but the first year is tight. Plan your budget carefully.

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