Think it depends on the soil you have there as to whether you add compost or not. Mine is heavy clay, and digging a planting hole and then filling it with looser stuff would just create a sump which would fill with water, and might waterlog the roots. So I tend to put a decent mulch of compost around after planting, but not right up against the base of the tree. Dig a hole about a metre square, or more if the roots require it. Make sure you don't plant trees too close together.
Have a good look at the base of the trees, you should see a soil line indicating where they were planted before. The knobbly graft should be about 10 cm above soil level I guess. Put a plank across the hole when its dug to help line the tree up.
I don't stake, but if you want to, then put the stake on the windward side of the tree, so that when the wind blows, it isn't knocking the tree onto the stake.
A stake about 10cm square by about 1.2 metres long will do. Inspect the tie regularly to ensure it doesn't cut into the tree as it grows.
