Variation 1 : (part b, bars 5 and 6).
This occurs in part B of the tune. They're just some low notes (low A and low D) inserted between the rolls on D. Use it the 2nd or 3rd time around. The important thing about any variation is that you don't overuse it. It's important that the listener can connect with the real tune. I think individual variations should probably only be sounded once during a recitation of the tune. Think of other different variations, or go back to the standard melody rather than over-using a particular variation.

Variation 2 : (part c, bar 4).
This is a run of notes which includes a run up to D: BCC#D. Let's deal with these first. Four notes are involved: BCC#D. The first three are on the draw, the last is on the press. Use fingers 234 for the first three notes. In this tune, finger 4 is also used for 4th note although there may be tunes where this is not the case (depending on what is coming next in other tunes). The notes which come after the run are BAGF#ED. The faster part of the video demonstration should make it clear where the emphasis lies. The slowed down part indicates the buttons/notes/fingers involved.