Assuming a person moves to work in British Columbia and is insured by the local single payer healthcare system, how are they supposed to access general practitioners and specialist doctors? Is there an official website that explains the process step by step?
In Canada, patients do not approach specialists directly. They do so either through their family doctor/general practitioner, or, if treatment was sought at a hospital, at that facility. (The latter should only be done in a perceived emergency.)
Once you qualify for the local provincial health care coverage (this is not immediate), all you need to do is to make an appointment with a GP accepting new patients. Some provinces have web pages showing lists of such doctors who have room for new patients. Make your appointment, and bring any records you can to fill in the gaps for the new doctor. If you need access to a specialist, request this via your GP - if you give sufficient reasons, he/she will be happy to make the arrangements. Here in Saskatchewan, generally, if you need a specialist appointment, your GP's staff will do this for you, at least for the initial visit. I expect the same is true in B.C.