Take the top lift and then go left (skiers right) across the small ridge. You wil see the vally open up below you.
Various of variations avalable. One of the best routs is to keep skiers right a bit and then keep skiing down and traversing at the same time. Val gronda is a vaste area, much like a big playground. Continue to the bottom and then take the cabin up again.
It can be very avalanche danger from the sides of the valley. Disentis is facing south so the sun can ruin this run.