What is the proper technique for using rudder pedals with toe brakes?
Unless you have extra long feet, keeping your heels on the floor of the plane is usually sufficient to keep them off the toe brakes.  Or pull your legs back a little and press with the balls of your feet near the middle of the pedal and not the top.  You'll get the hang of it pretty quick.

Learning to relax helps also, otherwise you'll fly with your legs all tensed up and just have the rudder pedals all mashed down all the time.  Very tiring.