Hi there. You don't need to wrap the whole tree, just the pot and the surface of the soil as it's the roots you need to protect. Do an internet search to learn how best to do it if you're unsure what to use. :)

It sounds as if the Acer has a small rootball. If it does, it shouldn't be put straight into a pot that's more than twice the size of its rootball, it should be potted (if that's how you want to keep it) into something 2 or 3 inches all round bigger than the rootball maximum, then potted on as it gets larger. One of the reasons for this is that largely unoccupied (by roots) potting compost in a tub can become 'sour' and unhealthy for your plant.

However, in pots, they roots are vulnerable to frost, although otherwise they are pretty hardy in the ground - the easiest way to protect it over winter is to find a spot in the garden that's sheltered from cold winds, pot your Acer into a more suitable size pot, then dig a hole and bury the pot until spring, then remove it. You can leave the rim of the pot just showing above the soil so you can find it easily in spring. Don't bury it in the ground before you have to, that is, if you start getting really low temperatures from early November, sink the pot at the end of October. Equally, don't leave it too long to take it out next spring - as soon as you see any hint of growth or the winter is over, remove it.

If you don't have a patch of soil, then other things must be done instead, so if what I've suggested isn't possible, add a comment below.