Boards for wooden fences come in many styles, from individual slats such as a picket fence to full panels for privacy fences. Most of them are suitable for installation with a properly sized brad nailer. A nailer that contains 2-inch nails easily handles even a 1-inch-thick fence board. An experienced carpenter can pound six nails into a fence board in under 20 seconds with a traditional hammer, while a brad nailer in the hands of a novice who has used it for only an hour can insert six nails in under 10 seconds.
A cordless brad nailer gives you more flexibility, but it doesn't deliver as much power as one connected to an air compressor. However, using an air compressor outside for a fence requires a nearby electrical source and necessitates hauling a heavy compressor down the whole length of the fence. A compressor should not be used with an extension cord. Adding a portable generator along with the compressor provides immediate access to power, but it adds another large piece of equipment you have to move along the fence.
In its most basic deployment, using a brad nailer is as easy as placing the muzzle against the board and pulling the trigger. The greatest danger is firing the nailer twice in a row, which leads to the second nail hitting the first and possibly bouncing back to your face. Like any gun, it should never be pointed at someone, your finger should never be on the trigger unless you are ready to nail, and you should always assume it is loaded and ready to use.
Brad nails are flat compared to regular nails, which are round. This allows brad nails to travel with the grain of wood, so they may slip sideways when you want them to go straight. Holding the nailer so the flat portion of the nail is cutting through the fence board grain instead of sliding between the grain helps to alleviate that problem. Keeping the nailer at full power also helps it punch through the board instead of twisting in its path.