If you want to do your own sprinkler system to save money there is one thing you should know. Don't dig the trenches by hand. It's been done before, but it's totally not worth it for most people. The only way its maybe worth it is if the ground is super soft to begin with and/or the yard is really small.
This is another idea that must be done away with. Trenching companies Trenching Guys home and trench for the same price as renting one and doing it yourself. In addition, they use a better machine than what you can rent. Their trenches will be wider straighter and better than your trenches.
Paint the lines for your trenching guy with marker paint. You will mark the perimeter and where you want your boxes. If the yard is over forty feet wide, add a line of paint for every twenty feet. Typically you will do the perimeter in the front and the perimeter in the back with one or two lines in the middle. If you are using rotors, put the trenches 20 feet apart. If you are using pop ups, put the trenches 12 feet apart.
Make sure Blue Stakes gets called before someone digs. Blue stakes will ask that whoever digs should be the one calling in. Make sure it gets done because the consequences can be quite disastrous.