Every string is labeled with the letter of the note it plays.
Just place the bow over the letter of the note you wish to play, and bow that string. The bowed psaltery is based on medieval instruments which disappeared a thousand years ago, when the ancestor of the violin appeared. For anyone older, it's an instrument you don't need an instructor or need to read music to learn to play. My Bowed Psalteries are mostly made from Poplar with a Spruce soundboard for a rich resonant sound.