DFW airport is pretty spread out. There are 14 or 15 (!) spots to get a shuttle, basically, one near each exit from the gate area / bagage claim. The shuttles at DFW are called "shared ride" on both the website and the signs, and they are adjacent to the taxi stands. Find it on the upper level of Terminals A, B, C and E, and on the lower level of Terminal D.

Are you and the other people flying in from different places or different airlines? If so, you should plan a specific meetup place. The airport website should show the terminal and gates for each airline (except AA, which is spread across several terminals). Any flights coming directly from Canada will arrive in terminal D, the international terminal.

If you are coming in to different terminals - if you have no checked bags, use the skylink train before leaving security to transfer to other terminals. If you have bags, look for the Terminal Link bus on the upper level bag claim to get a ride to other terminals.

Finally, consider a meeting place inside the terminal. If you're coming from different places, you may be waiting a while, and your Canadian blood may find July temperatures in Dallas a tad on the warm side...