Call your city officials to see if they require a permit, or if any part of the system needs to be installed by a licensed plumber. Then "call before you dig" so that you do not break any buried gas, water or electric lines.
Map out your system to determine which sprinklers are most appropriate for your yard, where you will place them and where you will bury the pipe. Place a flag at the future location of each sprinkler head and use marking paint to mark where you will dig the pipe trenches.
Dig the trenches using a trenching shovel. The recommended depth for trenches is 8 to 12 inches deep to ensure that the pipes are not damaged if you have your your lawn aerated/plugged.
Lay the pipe into the trenches and connect using the appropriate connecters. If you use PVC pipe, use PVC glue. If you used poly pipe, use hose clamps or crimp-on connectors.
Connect the sprinklers to the pipes in the previously mapped locations.
Install the irrigation valves in an irrigation box or above ground, depending on your preference, and connect the sprinkler pipe to the valve. Be sure to turn off your main water supply first.
Connect the irrigation valve to the main water supply.
Wire the timer valve to the timer and set the timer to your preferred watering times.