Perhaps the best thing you could do would be to have a look at a book on Fruit growing and see the various forms of apple trees and the way in which they are created.
There are 2 forms of cordon, one where the tree trunk is vertical with branches coming out at right angles to it and trained along horizontal wires and oblique where the tree is planted at an angle of 45 dgrees and again the branches come out and are trained along horizontal wires.
Which method you choose depends on the space available and the number of trees you wish to plant. Oblique cordons are usually planted closer together.
Growing cordons is just a matter of pruning and tying in.
First job though is to put in your posts and wires if growing in the open or wires if growing against a fence or wall. Usually 6 feet is sufficient for one cordon. Wires about 15 inches apart.
Plant upright cordon in the centre and tie to the wires, do not damage the tip as you want the tree to grow up until it reaches the height you want it to.
The aim is to get side shoots to grow out along the wires, so any growing in the wrong direction should be removed and any in the correct place gently tied to the wires. If they are too thick to bend easily then lower them in stages.
Then as the tree grows tie in any new side shoots required and remove unwanted.
Further pruning advice is probably best obtained from a specialist book on the subject.
