You don't, Murray. The Mountain dulcimer lays (usually) across your lap or on a table top. The nearest string (or pair of strings) to your body are the melody strings. These are pressed down on the fret to note the melody, and the other two are strummed open to create drones. That is why tuning is so important on a Mountain dulcimer. It is not a chromatic instrument--meaning ALL the notes are not there all the time. What notes are there depend on what tuning/scale/mode you are in......you still with me?

Dulcimer has a fret board similar to a guitar, and the melody is fretted, but the chords are droned (in Trad style). The lap dulcimer can also be finger fretted, finger chorded, flat picked like a guitar, or almost anything you want or are able to do with it.

I have heard it sound like a guitar, dobro, lap steel, (plucked)harp, piano, violin and hammered dulcimer if you beat on the strings with a pencil or something. It's a really weird instrument.