To prevent the drain from becoming clogged with grit or debris, place wire-mesh squares over the drain in the bottom of the fire-pit.
Safety Alert: Working with gas lines and flammable gas requires you extreme care. If you are uncomfortable doing this alone, a professional can help you with this portion of the kitchen installation.
The next step is to install the gas burners, or log lighters, in the bottom of the pit. Log lighters are available from home-improvement centers and typically require no tools for installation. They simply tighten by hand. After making certain that the pre-installed gas supply to the fire pit is turned off, remove the caps from the gas connections. Then set the log lighters in place and screw them onto their connections (Images 1 and 2). The log lighters come with a large hole at the base which can be opened or closed to varying degrees (Image 3) to control the gas-to-air mix, and thus the size of the flame. There are also gas-jet holes along the length of each log lighter to allow the gas and flame to come out (Image 4).
Once you've checked and adjusted the log lighters for proper operation, turn the gas off, allow the elements to cool and turn the log lighters so that the holes face down. Both the gas holes and the air-inlet should face downward to provide even dispersion of the flame throughout the rocks, and so they don't become clogged or filled with rainwater.
Once all adjustments are made, and the protective cages are in place, add the lava rocks. These rocks are specifically designed to handle heat and are commonly used in fireplaces and grills. Place rocks under and around the log lighters first so that the weight of the rocks on top won't bend the them. Now fill in the center of the pit with more rocks — to a depth of about 4" — to complete the fire-pit.