Union apprenticeship sign-ups near Dallas - any advice?

A local apprenticeship programme is taking applicants for the next intake. I do not usually post, so bear with me. The application needs a diploma or equivalent, a driver's licence and a short aptitude test. 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.

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