Pilot lighting instructions are in your installation instructions that came with the lighting control. They can also be downloaded from www.RasBox.com, specifically at http://rasmussen.host4kb.com/category/51/0/10/Installation-Manuals/
In a nutshell:
Ensure the gas is turned on to allow gas to the fireplace.
If the log set has a switch on it, place it in the OFF position.
Turn the safety control valve knob to the pilot position. At the pilot position you will be able to push the knob the maximum amount toward the valve.
Push and hold the knob in for a time sufficient to replace the air in the pilot line with gas (this can sometimes take up to three minutes, as the pilot line is very small, as is the amount of gas flowing to the pilot).
While pushing the knob in, light the pilot with a match (or push the button of the piezo ignitor, if equipped). Continue to hold in the knob with the pilot lit for 30 to 90 seconds, or until such time as when you release the knob, the pilot remains lit.
Once the pilot remains lit, you may turn the valve to anyplace up to and including full on to allow gas to flow to the main burner.
If you have a remote control, ensure that the batteries are fresh in both the hand-held transmitter and the receiver that is usually located in the fireplace.