The glissando is best accomplished if you have some thumb nail, or are wearing Alaska Piks. Tilt your thumb nail slightly so it can sail over the tines as it moves outward, plucking them gently on the trailing side.
Three adjacent tines make a triad. Four adjacent tines make a 7th chord. Five adjacent tines make a 9th chord. The tricky part is knowing which tine to stop on.