Here's some other good information from Ben Hooper that was posted on the other site.
Tips on growing/pruning caged apple trees
Planting year (1st leaf)
1. Stake your tree immediately after planting (1/2" elec conduit is what I use). And 8' hardwood 1" stake is also excellent. Mulch with gravel/peastone, crushed rock etc. out to the cage diameter.
2. prune the main leader back to 36 inches for 5/16-1/2 diameter whips and back to 4' or so for 3/4" whips. For feathered (branched trees) cut them off 18" or so above the top feather. When heading back, cut just above (1/2") a bud at a slight angle, to not damage the "root" of the terminal bud.
3. Fasten the tree to the stake with aglock, string etc, with some breathing room.
4. Let the buds sprout and asess the condition of the tree. If it is lively, there will be lots of buds sprouted out 1/2" or so and green. Maybe some flowers (remove all flowers year 1) If the tree shows only a little life by mid June, let it sprout more and start training next year.
5. When the buds are out 1-3 inches, the top several buds will look like they are all trying to become branches. Leave the top bud and remove all the others below, within 4 inches. If growth is weak, fertilize with 6 oz 10-10-10 around the base but not touching the tree, scratch into the mulch.
6. If lower branches head north and try to become a leader (very likely), tie them down with kitchen string, weigths, clothes pins etc. keep them weak.
7. If you have a green thumb and decent soil, you will get 2-4' of leader growth of your selected leader.
1. In March (or before bud break for your locale) prune 50%-75% of the branches inside the cage off as close to the trunk as possible. Any nub left will resprout (dutch cut), so try to get it close. Start bottom work up.
2. If your leader growth was more than 4', cut it back to a ripe bud at 4'. Score above some buds above your cage, where you want your lowest branches. For B118, 5-6' off the ground is about right I think, but variety will play a part in branching habits so make the call.
3. If your leader growth was less than 2', repeat the leader process by repeating step 5 above, and do not score above any buds. Did you fertilize?
4. On your new branches, try to get good angles on the branches, again, variety dependent, you may need to clothespin and tie some branches out....use limb spreaders, weights, whatever.
6. After your tree is taller than 8', you should practice dormant season pruning on the top of the tree, to maintain leader growth. Basically allow the tree to produce several leaders ever year, and remove the ones you don't want in March. This is normal dormant pruning as done on mature trees. Eventually your tree, will produce high branches that will shade the lower. Suckers (upright whips off a branch) will form, and should be removed dormant season also.