If the young grafted tree:
Flowers or begins to form fruit…
The same caution still applies to your young tree:
Do not handle the upper portion of the tree above the graft union, it is still too weak and vulnerable.
The below photo sequence should provide a useful guide:
Pinch out all flower buds as shown above. Newly formed fruitlets can be treated in the same manner.
A young grafted tree does not have its fruit bearing structure established yet in order to carry fruit through the season. Allowing the tree to bear fruit in its early years risks damage to the tree. The weight of mature apples may apply too much stress to its young structure.
Early fruit bearing may stunt the tree as it slows vegetative growth. By dis-flowering the young grafted tree, the trees energies will be applied to growing a good fruit bearing structure for future years.