Starting out in the 'Place du Snow' take the path that goes between the 'snow' and 'allegro' buildings. Walk past two chairlifts, the 'Stade' and Lac Intrets' and keep going along the trail that follows the Avoriaz lake. Follow the track until it forks and take the trail back round the other side of the lake back to resort.
If you want to make the walk a little longer go along the path that heads uphill at the fork, passing a small lake and keep going until you reach the Chavanette pass. Here you will be on the French/Swiss border and can admire the views. To head back to resort take the trail back and then follow the lake around the other side and you will be back in Avoriaz.