The hole simply needs to be as big as the current container. add some plant food made for trees, and lots of water to start.

It may be cost effective to have neighborhood kids plant them, but make sure it is done correctly. Make sure the root system is loose when planting and plant it high, maybe 2" above the ground. Water them well and mulch them, but dont pile the mulch on the trunks, it can cause rot and fungi to breed. Call your local AG extension office for advice or get estimates from 3 or more reputable Landscape contractors. Expect $50.00 or more a hour. And providing there is no major problems, shouldnt take more than 1.5 hours!