A few things to know.
First, to get to Avoriaz, you generally pass by Morzine. If Morzine has snow, you can be sure Avoriaz will have what you need. When you arrive at the Avoriaz resort, you need to go to the loading dock to unload your car, and then you have two choices. Either your car goes in a covered parking lot (€100 per week) or in an outdoor parking lot (€75, I think).
Once you've made your choice, you have another to decide. You can either wait for a horse-drawn carriage to take you down to your accommodation (€13) or take a large toboggan (€1).
Once settled in, you'll find everything you need right there (Sherpa supermarket, Carrefour bank, Crédit Agricole bank, restaurants, etc.). Now all you have to do is enjoy the snow during your stay. For the return trip, please note that horse-drawn carriages are available from 8:30 am, but snow groomers can also pick you up at any time.
I hope this information is helpful.