Union apprenticeship sign-ups near Portland - 5 weeks in

I heard of an apprenticeship with paid on-the-job training for people changing careers. This is my first time dealing with any of this. Classes are in the evening and work is during the day. What do you wish you had known?

Visit the training centre in person if you can. Seeing the classrooms helped me decide.

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