You need a dynamic light to be able to use the light switches. Create a room select a light, press y to make dynamic (Should turn green instead of red). Place the light on the level. Put a light switch against the wall and right click on the properties. Then in the IFUSED section put in the name of the light entity.
Test the level and the light should react to the switch.
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"What is this talk of 'release'? Klingons do not'release' software. It escapes leaving a bloody trail of developers and quality assurance people in its wake!"