Just look into building a bike, and take it from there. There are lots of people without your background who are building bikes. Or consider working for bike friday out west. They do run people through a process. Possibly look into the european scene since some of their laws require apprenticeship. Japan still has quite a few apprentices in various crafts. You can find quite a few interesting reports online.

Apprenticeship in the traditional sense is basically broken in the manual arts, and it was never strong in the US to start with. The old arts aren't doing so darn well, and apprenticeship is a whole other demand for which the economics no longer exist. Traditionally it involved spending 4-7 years in what amounted to near slavery, for the privilege of learning a craft. There is 4-7 weeks of learning in there, the rest is payback for the terminal economics. Most people these days don't want to do that kind of thing, from either side. The alternative is learning by doing, either working for someone else or figuring stuff out for yourself.