Open DrVenom8's brightmaps with Slade3 and study how he set up the folders and what they contain. Compare with the instructions in the WIKI.
Creating your own brightmap images is best done with a program like Photoshop, if you have it, or Paintshop Pro, Paint.Net, GIMP, Paint, etc..
For example, for the switch textures SW1STARG and SW2STARG.
If you want to use DrVenom8's brightmaps in your maps without creating your own, then open the game ini file and add
of course, the path in your system may not be the same as mine.
Always have fun creating your maps.Kappes Buur