One great technique for working with a chord progression is to create an effective sequence of notes. You could have an advanced chord progression where the notes move with each chord change or you could keep things simple. Today's lesson is for reasonably advanced players. But, we'll break it down and so that all levels of playing can some idea of what's going on.
First up, notice that the entire piece is in triplets. For practice purposes you should be playing this at about 120 beats per minute. Speed it up if you can and on the flip-side slow it right down if you need to. Whichever approach you take keep it tight!
This is a simple D-C-G-D chord progression. In itself that progression is not absolutely true to music theory but is a standard in most forms of music. The first triplet in each bar is a D note regardless of the chord it is behind. The second triplet in each bar adds a little definition to clarify what chord belongs to that bar. Most likely it's your bass instrument or some other instrument which will actually define the chord.
Those groups of second triplets for each bar are: A-C-B-A. One way to look at those notes is in relation to the root note of the entire progression and work out their relative tone to that (5th, flat 7th, 6th, 5th) but we're not taking that approach here. Each of those notes is a harmonically relevant to the chord they play behind which becomes (5th, 1st, 3rd, 5th).
Last two sets of triplets are identical for each bar and are based on the D-Major scale because the entire progression is basically in the key of D. Theory-wise it all works great except for the C bar which contains a F#. The problem is there is no F# in the notes belonging to a C Major chord. It should be an F. The reason it works is because the repetitiveness of the notes gives a lot of solidarity, almost like they are saying, "we don't care for theory. Just deal with it."