newbie tuning question

I am so new to the noter style and the dulcimer the wrapper is still on, I was trying to work out “the water is wide”. I tuned in CGG, only because I liked the drone, but I’m unable to sing in that key..should I stick to more traditional tunings like DAA or DAG? I’m not even sure I was hitting the correct frets, but it sounded familiar .I guess my bottom line is how to find the key to match the vocals..