A good contractor will recognize new employees with potential and try to point them in the right direction and give them guidance.
My first construction job ever was in the Caribbean. I got placed with a group of Haitians, and we were all laborers. We never had a tool in our hands. We simply carried materials, loaded things onto the roof, set up scaffolding, etc.
On my third day on the job, the leader of the Haitians became angry at me and kept telling me to slow down. I kept pushing and the lead carpenter on the job noticed. The next day, the general contractor (my boss) pulled me aside and said "when you come in on Monday, make sure you have a tool belt, a hammer, a pencil, a speed square, a tape measure, and a razor blade."
I showed up that Monday with all of the required tools and the GC let me work alongside the lead carpenter. At the end of that first week, the lead carpenter lent me a book that he used to learned carpentry while he was in a union in Wisconsin. I spent all weekend reading that book and I had tons of questions for him when I returned to work the next week.
I never looked back. I have since worked professionally in every single residential construction related trade. I am confident that I can perform each trade at a professional level with the exception of welding. I can weld. I welded everything on my Land Cruiser and I've welded scores of hip plates over the years. But I'm not confident enough to say that I could perform at the same level as a good professional welder.
But HVAC, electrical, plumbing, roofing, siding, millwork installation, finish carpentry, landscaping, and irrigation are all things that I can perform at a top level.
That lead carpenter ended up being my best friend I have ever had and he taught me about a lot more than carpentry.