Career advice

Hello all,

I am looking for some career advice. I would like to work for a contractor to gain experience with building construction, preferably smaller buildings and/or homes. I want to eventually become a builder or developer myself.

Problem is Im a career changer, and from an unrelated field. I worked as an engineer for ~20yrs, so now im early forties and have no trade - which builders want to hire, for obvious reasons.

How do I get hired with a GC? What job could i possibly do for them? Perhaps estimating or proposals? I'd really like to work as a construction manager or his assistant. I don't mind physical labor (im in good shape), so I'd be happy to help with jobs like framing which I can handle with supervision of a trades expert.

Should I invest in one of the college certs - like the constr manager certificate, or renovations cert or estimating cert, or home inspection cert?

I'm not sure where to start, but I just want to get into the business and get my hands dirty. I'll do practically any job.

Thanks for any suggestions.