I'll dump what I can here. Hopefully it makes some sense.
2/4 time means each measure contains two quarter notes.
6/8 time means each measure contains six eighth notes.
To my knowledge, bagpipes cannot play chords. However, each "bar" should mainly use notes from a chord, one chord at a time, and certain chords move into other chords more naturally than others. That is why there are categories for the chords: "tonic" "tonic extension" "sub dominant" "dominant" to help get the order right.
"Tonic" contains: I
"Tonic extension" contains: III
"Sub-domianant" contains: II and IV and VI
"Dominant" contains: V and VII
pick one or more from each list and move down the lists, but you cannot move one chord value down; like III into II is wrong, and VII into VI is wrong.
Some examples are I - III - IV - VII or I - II - IV - V
You can also skip a category, usually tonic extension. You can skip sub dominant. Don't skip tonic or dominant - they are the foundation for music to work.
Some more examples are I - IV - V - or I - V - I - VII
A chord contains three or more notes. Begin on the note of the scale that the Roman numeral says (like the first note for I, the second note for II), then choose every other note in the scale to build up. Like C would have C E G, because you skip D and F.
Do this for all seven chords of your scale to figure out which notes are in them.
Intervals are the number of semitones between two notes, and a semitone is the smallest distance between two notes. For example, C and C# are one semitone apart. The names of the intervals are in this order: m2 (minor second), M2 (major second), m3 (minor third), M3 (Major third), P4 (perfect fourth), P5 (perfect fifth), m6 (minor sixth), M6 (major sixth), m7 (minor seventh), M7 (major seventh)
a triad is a type of chord made up of two "thirds", because the notes in the chord are three or four semitones from each other. A major triad has M3 then m3, while a minor triad has m3 then M3.
