HVAC career path: questions, help!

Sorry if there are threads already on this – I have been working in an office environment for several years now, seemingly unable to move ahead. I am looking for a career change, HVAC [and also plumbing] have caught my eye.

Specifically, I am looking for some feedback or guidance from somebody with knowledge in this field.

What / where / how to enroll in a program? Do I go to school first, then apprenticeship? Or both at the same time? What prerequisites are required?

Any other valuable info I would greatly appreciate.

Thanks