Just 1-Finger will get you there. Play along with one of the most classic of classic rock tunes.
This lesson video is for the 1-Finger version only, but the chord guide includes multi-finger shapes as well.
And if you're interested in learning a LOT more about dulcimer guitar chords, please check out the Complete Chord Guide. It offers options on different chord types, versions you could use instead of the ones I suggest, as well as the why's and how's of playing (technique). I think you'll like it.