Propagation of arborvitaes can be done best by clippings.
This is generally easier than it is on other plants, as the tree can literally be torn apart to make hundreds of smaller clippings.
Planting arborvitae clippings is easy to do, but takes some time before a mature plant grows
The clipping should be about four inches of new growth, and should be placed in a sandy soil.
After planting arborvitae clippings, a mist of water should be applied for a few seconds every ten minutes or so.
More information about planting arborvitaes can be found in a variety of locations. Internet sites have some helpful tips.
Local nurseries and garden centers would be able to provide good information about planting arborvitaes. There are also several books written about planting arborvitaes and other trees.