Measure out the area where you want to install the rock bed and place a stake in each of the four corners. A rock bed may be as long or as wide as you want. If you plan to resolve water drainage issues, position the rock bed so it starts where the water comes onto your property, then route the bed to the location where you want the water to end up.
Tie a string to the stakes to create an outline of the rock bed.
Dig out the area inside the strings until you reach a depth between 2 and 4 inches. Dig out the area. Once the dirt is dug, use a rake to rake out any rough areas in the soil, then tamp the ground with a metal tamper to create a solid surface to place your stones on.
Line the excavated area with landscaping fabric. Landscaping fabric prevents weeds from growing up into the rock bed but allows water to drain into the soil. Overlap each piece of landscaping fabric by at least 12 inches.
Remove the string and stakes from the area.
Outline the excavated area with larger stones such as large pieces of sandstone. Use a pickaxe to break up larger pieces of stone so they easily fit together. You may locate large rocks in your own yard, or you may purchase large rocks from a home-and-garden center.
Place a layer of smaller stones such as river gravel into the rock bed between the large stones. The smaller rock acts as the filtering media for water runoff.