I found it a bit of a struggle to get working, but the instructions are here:Looks great dude, have sent a PM asking about how you linked the screen with Mamehooker.
The Dragon King - Display Files: Displaying a Marquee on a Secondary Monitor
There is an extra change you have to make in the mame.ini for mamehooker to work - not knowing this was what gave me most trouble! You have to set this in mame.ini if you're using above mame 176
#
# OSD OUTPUT OPTIONS
#
output windows
Trying to use the MAME secondary monitor stuff just messed up the timings of the games with groovyMAME, so this was the only way I could get it to work.