There are relatively few third-party affiliate stations of Canada's commercial networks; they typically follow the schedule of an O&O in a nearby major market, but with opt-outs for local newscasts and other local programming, and may also simulcast that station's newscasts in timeslots where they do not air their own (essentially acting as a third-party semi-satellite).
The text describes how Canada's commercial networks have limited third-party affiliate stations. These affiliates operate similarly to owned-and-operated stations in nearby major markets, but with some exceptions for local programming and simulcasting of the network's newscasts during specific times when they don't air their own content.