not sure if it is a question about switchable texlights in general or just about the start off.. anyway..
make a func_wall (or what other entity you want to use for the light source) put the texlight on it, give it a name and set "Texlight style" to "grouped". Create simple light entity and give it the same name and also select "grouped" there. Set the light entity to whatever brightness and color you need it. And this combo is what you need to make switchable texlights.
To let them start off at each round start, simply use a trigger_random which triggers the the name of the switchable texlight, so it goes off.
Comments
make a func_wall (or what other entity you want to use for the light source) put the texlight on it, give it a name and set "Texlight style" to "grouped". Create simple light entity and give it the same name and also select "grouped" there. Set the light entity to whatever brightness and color you need it. And this combo is what you need to make switchable texlights.
To let them start off at each round start, simply use a trigger_random which triggers the the name of the switchable texlight, so it goes off.