Contact a local LGBT organization. There will be at least one in Montreal, maybe more. One of them will be able to point you towards a gender therapist. That is the normal starting place for the process.
It sounds like you know who you are and what you want, so it may be that you will not need the therapist for any significant length of time. But you will most likely need a letter from them referring you to a doctor for HRT. The therapist will likely be able to help you find a doctor to write you the prescription.
I have a regular GP for routine medical stuff, which I don't need a lot of, because I am generally healthy like you. I go to a different doctor for my HRT, one who specializes in trans health care, and therefore has the expertise to monitor my blood hormone levels.