http://www.cic.gc.ca/english/information/applications/fc.asp
Read through the application guide and all the forms to get a general idea.
The sponsor complete part one and the applicant completes parts 2 and 3. All parts are mailed together to Mississauga. They will assess the sponsors eligibility and if approved will send the application to London for processing of the PR application.
A medical is required and must be done by a DMP http://www.cic.gc.ca/dmp-md/medical.aspx
The sponsor will need an option C printout or if you're residing in the UK, pay stubs from the last year. The sponsor will also need to include proof of plans to return to Canada. Job offer/searches, letters from family offering help financially or a place to stay, shipping enquiries, school offers... anything.
Also pay all fees up front to avoid later delays, total is $1040.
Read through forms and guides and if you have more questions ask away.
Acronyms... PPR - passport request. London no longer request the passport for UK citizens as they are visa exempt. The purpose of the passport request was to issue a one time entry visa. But since UK citizens do not require a visa to enter Canada, this step has been skipped. It saves time. Now the COPR will be issued directly. The confirmation of Permanent residence is the piece of paper required for landing at the port of entry in Canada.
Once you land you can get a SIN, apply for healthcare, etc. The PR card will arrive automatically in the post 4-6 weeks later. You provide the mailing address for PR card at time of landing.