Standing upright, place the front foot straight and the back foot with the forefoot on the slackline (about one foot length apart). In this position, bend your knees until you can sit with your buttocks on your heels.
Easier: Perform the exercise close to the attachment.
Harder: Touch the slackline with one hand (line grab); stand up again from the squat, take a step forwards and squat down again (other forefoot).