You only need to use the support gcode files if you have a dual extruder.
Then you can use the start/stop support gcode files to switch to the extruder with the support plastic.
If you only have a single extruder then you don't need anything in the support gcode files.
Bob Morrison
Wörth am Rhein, Germany "Luke, use the source!" BLOG - PHOTOS - Thingiverse