There are three holes in the upper back of the seat maybe still with a plastic plug in place (one in middle position and either side). Your car seat should come with a threaded bolt/bracket thingy that will fit the holes, and then your car seat tether will clip to that. 2 pics attached...one of the required clip that comes with the car seat (or available separately anywhere you buy a car seat), other pic shows an old style attachment in the middle position of my wagon, but thread is the same as all new ones.
