Dig a hole about one spade depth. Replace some of the topsoil so the bud union is just above ground level.
Trim any broken roots and spread them so that the strongest roots, and if possible the bud union, are facing the prevailing wind. Replace the remaining soil and mound slightly because the disturbed soil will gradually sink as it compacts.
For good measure, sprinkle a small amount of slow release blood and bone fertiliser on top of the soil around the trunk, but be careful not to allow the tree roots or trunk to be in direct contact with the fertiliser as this may burn them.
It is difficult to advise on the distance required between trees when planting because much depends on available space, growth habit etc. Generally, three or four metres is ideal if the trees are to be grown in a vase-shape. If room is restricted consider multiple planting (below) and central leader or espalier methods.
Plant three trees (as pictured above) in the same hole about 30cm apart.
Good results can be obtained by judicious pruning to prevent too much inter-weaving of the branches. Prune the three trees as if they were one, removing branches in the centre triangle. A dwarfing effect and earlier fruit will result because the trees are in competition with each other. Feed and water weaker trees to help compete with stronger varieties.