We are going to be in Canada already and waiting for the visa...so once they issue the visa what do i need to do to? Would i need to exit canada and re-enter?
Most people just do that, since it's generally quicker and not much hassle. You can literally drive to the nearest border and, assuming entry into the US is not an issue for you visa-wise, you can tell them exactly what you're doing and then turn around and come right back to the Canadian side of the border. You would then "land" there at the Canadian immigration office.
However, if you have valid temporary status and can prove it (passport stamp, visitor record, etc), then I've read that you can also schedule a landing appointment at the nearest inland CIC office and just land there. The drawback to doing this is that there can sometimes be a long wait time for these appointments, depending on how busy your CIC office is.
There have likely been others on this forum who have done this, so a forum search may turn up posts by others who have landed inland and give you a better idea of what to expect.