Thew "star headed" screws are Phillips screws that fasten the pedal plates in place. Don't loosen or adjust them. The 3 mm Allen head screws at the back of each pedals (where the coil spring can be seen) adjusts the release tension.

Turning them in (clockwise) tightens the release and backing them out (counterclockwise) loosens the release tension. Don't back them out all the way or they will come out and you will have the devil's own time getting them back in. These adjusting screws should "click" as you turn them so count clicks to be sure both pedals are set alike.