First things first. Does it even have a metronome? At the back of all good technical manuals is an index of words. Look under 'M'.
If it doesn't have a metronome, throw it away and buy a better keyboard which does. We live in a disposable world.
Wait a minute.. you sure the teacher thingy didn't mean your daughter should use a metronome, not the metronome. There are stand-alone metronomes you know.
-tek