Water it well. You can substitute cottonseed meal at the rate of 9 quarts per inch of diameter. It takes more, but it costs less, and it's organic. Cut back if the tree is growing too well. Your tree will do best in sun and a well-draining, slightly acidic soil.
Seedlings can take many years to bear fruit.
The grapefruit information applies to satsumas, and little or no pruning is required. Or use the cottonseed meal. My night-blooming jasmine, hibiscus and saucer magnolia have outgrown their containers. I have no garden space. Since most plants are about to enter dormancy, I would wait to prune the jasmine until early spring when it is about to begin another growing season.