@evilcookies98 Okay, figured it out. In the default script file, there's a section called AutoStartEvent. You'll have to arrow down, until you hear endFunction. Go to the start of the line and press Enter. Arrow up to the blank line and paste this line.
ToggleScreenShade ()
Control+s to compile. Pressing JAWSKey+0 opens the script editor. Control+Shift+d puts you into the default script. Control+f to find things.