New Quince Tree
If you are not yet ready to plant it in its final place, I would either plant it in a pot or find a temporary planting site. I assume it is a bare root plant so it will at the very least require water at its roots while you are waiting to plant it. In order to ensure its best chance of survival, I would recommend removing it from the packaging and planting it as soon as you can.
The Quince will require a warm, sunny sheltered site. It will like plenty of organic matter added to the planting site in order to produce a good crop.