An invisible fence is an aesthetically pleasing way to contain your dog and make sure that he's safe. The options for invisible fences include those that correct behavior by use of a mild electrical charge and those that correct behavior by spraying citronella. Citronella is the harsher of the two corrective measures and is less common than an electrical charge. The corrective measure is triggered when the dog strays beyond the boundaries of the invisible fence.
The Quickest and Least Effective Method
The reason the invisible fence is invisible is that the wires that mark the boundaries of the area you wish to contain are buried beneath the surface of the ground. Some people choose to go an easier route and either staple the wires to the ground itself or staple the wires to an already existing traditional fence. With both of these methods the wires aren't likely to be perceived unless looked for. However, dealing with the wire in this way increases the likelihood of the wire breaking and thereby disabling the invisible fence. A wiser and more effective method is to bury the wire at least two to six inches below the surface of the ground.
Burying the wire beneath soil is relatively easy. Using a flat-edged shovel, puncture the ground and wiggle the shovel back and forth a bit to create a very narrow trench. Continue this, shovel width by shovel width, until you mark out the entire perimeter of the fence. An alternative method would be to purchase or rent a trench digger, but because the trench needed is so narrow a trench digger may be more trouble--financially and otherwise--than it's worth. Once you've got the perimeter marked you can tuck the wire in and tamp down the soil to seal the wire in place. The deeper you place the wire the less likely it is that the wire will be displaced or damaged by landscaping work.
More difficult than embedding the wire in soil is when you need to cross a driveway or sidewalk. With a circular saw you'll need to cut along the pavement where you wish to lay the wire. If you plan on placing the wire where there is already a clearly defined joint in the concrete, you can cut along that joint. If not, cut as needed. Make sure you use a saw blade that's wide enough for you to insert the wire when you've finished cutting. Insert the wire, but keep in mind that you'll want to make sure that it's embedded extra deep on either side of the concrete so that the future use of edging tools won't cut the wire. After the wire is inserted you'll need to seal the cut with self-leveling mortar.