How do you walk down on a guitar?

Answer 1

Assuming I have understood your question correctly, walking down on a guitar basically means stepping down note by note at a steady pace while playing. Similar to walking down some stairs. It does not refer to any particular notes or scales, just as long as the notes generally move downwards. Or if you are talking about a particular song, it will refer to the one used in that song.

Answer 2

There are many popular walkdowns, they being simply transitions from one chord to another. Walkdowns are dependent on the key you're playing in, of course. For example: While playing a C-major chord, strike the 5th string (A) on the third fret, being played by your ring finger. Remove your ring finger, move your middle finger up off the fourth string/second fret to the fifth string second fret, play that, then remove your middle finger, playing the A string open while changing chords to an A-minor, then resolve the mess by next changing chord to G-major. A simple and often used blues transition is the 2-string walkdown to E-major:

Place index finger on second string/third fret and middle finger on third string/fourth fret. Strum downward once on the first three strings; then move fingering down one fret (index finger on second string/second fret and the middle finger to the third string/third fret), strum downward; then move position downward one more fret (index finger on first string first fret and the middle finger on second string second fret), strum first three strings again; then play an E-major, strumming downward again to resolve the transition. Of course you can strum the tansitions a couple of times, depending on the tune you are playing, to accentuate the downward transition. (Note: You can do the same walkdown to E-major above, using only the index finger, making it less full in tone.) Experiment with such "walkdowns' between all sets of chord changes, trying to determine what string or strings to use that will sound best when making your tarnsition between chords. The technique livens up any song and adds much to a jam.