well we need to know exactly what style tensioner you have. there are two..
one style you stick a flat blade screw driver into a hole and 'ratchet' it down. the other style requires you make a small holding strap out of like a piece of clothes hanger. its tiny, maybe less than a 1/2 inch long, you bend it to hold it together. its hard to explain, the haynes manual should explain both ways in greater detail with pictures as well.