I always find the form on the CIC website by searching there for "privacy" - it's the first link that comes up for me.
To have someone in Canada request, they need an executed IMM 5475 form to include with the request. The charge for that is $5 (can be paid for online as I recall.) If YOU are in Canada, you can request it directly (you don't need to go through someone else) and there is no charge (you check off a different box on the request form.)
The service standard is 30 business days (hence 6 weeks) although most people report receiving the response sooner than 30 business days.
Note: you only want computer notes. If you request a PHYSICAL copy of your file, the visa office will pull your file and copy its entire contents but people report that this slows down the visa office's processing of your file.
I read one person's posts in which they requested their CAIPS/GCMS notes every five weeks throughout the processing of their file. Personally, I think this makes tremendous sense, because it means that you can keep track of its status and address issues as they arise, rather than waiting for the visa office to ask you for something. It also is useful if you are called for an interview or if there is any issue or concern raised by the visa officer.