Good Day,
Training requirements for the Primary Reserve vary depending on the unit you're joining and the occupation that you would like to become. Unfortunately we cannot give a simple answer to your query above. I highly suggest that you visit the Reserve unit that you're interested in joining and speak with the unit recruiter and the individuals at that unit.
Just as an example, the Naval Reserve only does Summer BMQ where you have to be gone for 8 weeks. The Army Reserve has co-op BMQ, weekend BMQ and summer BMQ. Beyond that each trade has it's own training time, some occupations have really short courses (2-3 weeks) for their trade course, others can be closer to 3-4 months for the Reserves.
Best Regards,
Sgt Laen