First, don't do it now as it is completely the wrong time of year, even for a container grown tree. Trees should be planted ideally in autumn just after the leaves have fallen and as they move into dormancy. This avoids any pressures on the young tree from drought, and gives them a full winter for the roots to start growing down into the soil.
You could use the summer to start preparing the growing hole.
Remove the turf with a sharp spade and stack it somewhere in the garden with the grass side downwards as this will make a good fertile loam you can use after a year.
Make your planting hole WIDE rather than deep. Traditional advice was always to dig a deep hole and to put compost in the bottom but this is now recognised as wrong. Copy what happens in nature, where compost and feed come from the surface layers.
Dig a hole a good spade's depth deep and around six feet in diameter (if you have the energy.) Remove the soil on to a plastic sheet and pull out any perennial weeds.
Use a fork to loosen the soil at the bottom of the hole so that the roots which take up water can penetrate.
As feeding roots grow near the surface, mix some good garden compost with the soil you have removed, to make a nice fertile mixture.
In the dormant period when the trees leaves have fallen, plant it in the hole and
firm in the soil around the tree, making sure it is not planted any deeper than it was in the pot. Be sure to stake it by hammering in a stake at an angle of 45 degrees to the trunk on the windward side and tying the tree to it with a tree tie or an old piece of bicycle inner tube.
Next spring and summer, as the tree starts into growth, make sure you water it well especially if the weather is dry. Many young trees suffer in their first year after planting.
Keep the area around the tree free of grass for at least several years and put grass cuttings as a thick mulch around it to keep in the moisture after watering.
If your tree is in a container, make sure the roots are not wrapped around in a circle inside the pot and pull them out if they are. In fact, by planting in the dormant season you can shake off much of the compost in the pot as this is probably pretty exhausted stuff by now.

thanks, very helpfull