This video is fairly long. To skip to a topic you can scroll ahead to this time:
At 0 min. 00 sec: Description of the instrument
At 2 min. 20 sec: Set a free standing bridge
At 5 min. 10 sec: Understanding dulcimer frets
At 9 min. 25 sec: Easy playing methods in DAA tuning
At 12 min. 05 sec: DAD Tuning
At 12 min. 55 sec: DGD Tuning
This video gives you basic information about what you can do with a dulcimer.
Here is more detailed information to help you get started.
If you are just starting to learn about playing music this very basic lesson may help you get started.
Play chords to accompany a person playing the melody.
Find music tabs and more information on the Internet.