No rush, Don.  Just enjoy yourself, but feel free to reach out if any questions pop up.

Contact me by personal message, Don, if you have more questions on this stuff. 

By the way, in explaining things to you, I've made a further change in the tab.  

In measure 2, instead of getting the F# on the 2nd fret of the melody string, I will now indicate it as the 5th fret of the middle string. So I would use my ring finger on the 2 at the end of the 1st measure and then slide that finger up to 4 for the second measure, leaving my middle finger ready for the 5 on the middle string.   That way the move up happens a little earlier, but it involves the same finger on the same string just sliding up two frets and then the hand is in perfect position for the next two measures.

Don, I'm not quite sure what you mean by "guideline."  A note on the melody string can be found 3 frets higher on the middle string, and a note on the middle string can be found 4 frets higher on the bass string.

If you're looking for guidelines about when you would want to move to another string rather than stay on the string you are on, I think you have to examine the specific notes you are playing and your hand position.  In my playing I try to follow a few golden rules: 1) minimize left-hand movement; 2) moving from one chord position to another, try to keep at least one finger on the same string; and 3) keep your left hand in a chord position as much as possible.

If you are not playing chords, some of that won't mean much to you, but you should still understand the principles.  Let me address the question of when to shift to another string by looking at the first two lines of a tune I just tabbed out last night for my dulcimer club meeting this weekend.

The melody (pick-up note aside) is entirely played on the melody string in the first two measures, but in the 3rd measure I get the melody note of G on the 6th fret of the middle string. Why?  That same note is found on the third fret of the melody string.  But look at the subsequent melody notes; they are found on frets 5 and 7.  So rather than have to jump from 3 to 5 and then to 7, I just move my hand up, catching the 6th fret of the middle string with my middle finger, and then leaving that finger down, my ring finger falls onto the 5th fret of the melody string.  Those fingers stay down as I reach with my index finger (or thumb) to 7, then lift it up and hit the 5, where my ring finger can still be found.  And then, moving to the 4th measure, that position with my middle finger on the middle string and my ring finger on the melody string just slides down one fret from 0-6-5 to 0-5-4.

So by using the middle string for that one note, I am able to get almost two entire measures with my hand in the same position.

Notice that I said "almost two entire measures."  The last note of the first line is an F#, and I indicate it on the melody string at the 2nd fret even though it is the same note as the 5th fret of the middle string, where my finger already is.  Truth be told, I probably play that note on the middle string there most of the time when I play this tune. However, the 5th measure obliges us to move all the way down to the 3rd fret for the melody string and then everything that follows is down by the nut.  So to facilitate that move, I chose to tab this tune out using the 2nd fret of the melody string rather than the 5th fret of the middle string.

Obviously, there is no hard science to this stuff. You just try to figure out what will work best for you, meaning what will facilitate you finding the melody in the easiest way possible, with the least amount of movement.

GOT IT!  Is there a guideline to moving from string to string?

Don, @Strumelia's correct. A lot of people cannot pick out simple melodies on the dulcimer. If you can do that you are ahead of the curve.  Just keep working at it.

If you want to challenge yourself, try to pick out melodies going across the strings as well as up and down a single string.  If you are tuned DAd, just add 3 to the fret on the melody string and you'll find that same note on the middle string.  

Here's a challenge for you:  Play "Three Blind Mice."  You will begin at the second fret of the melody string.  But when you get to "They all ran after the farmer's wife" you will have to move up to 7.  However, instead of continuing on down the melody string for the end of that phrase, try to move to the middle string.  You will finish the song on the 3rd fret of the middle string instead of the open melody string.  See how it works out.

Obviously, drone players will always stay on the melody string. But those of us who include chords in our playing try to minimize our hand movement.  Learning to find portions of the melody on the other strings will help you achieve that goal.

Being able to pick out a tune on your instrument is an ability that many folks wish they could develop.  Just saying!   :)

No need to be embarrassed.  That's how you learn an instrument.  I still have trouble playing from tab but generally get a tune in my head and then find it on the fretboard.  Sometimes if I have trouble with a spot or two, I'll turn to tablature to see how someone else plays the tune, but then I just go back to the instrument.

I pick it out on the melody string whether I hear the tune in my head or hear it on YouTube or elsewhere. It's how I learn to play any tune. Which means I generally don't consult a tab or sheet music. As I pick out a tune I usually do have to write it down bit by bit.

Does anyone else hear a tune in their head and have to pick it out on the melody and middle string?