Hi Randy,

In a nutshell, it means this:

A standard major or minor chord contains 3 distinct notes:
the "one" (the root note, or the note the chord is named for)
the "three" (three tones up the scale from the "one)
and the "five" (five tones up the scale from the "one")

"Add 2" or similar language (sus4) means to ALSO add in the second note of the scale, (or the 4th, or the 7th, or whatever is called for)

Make sense?
-Lisa