This part I focus on using one upper structure triad and mixing it with the 4 notes of the dominant 7 chord to create a melodic fragment.
I will use the key of C as an example in parenthesis.
In summary, we are using a Maj Triad built off of the 6th scale degree of a V7 chord that leads to I. This could be the V7 of a ii-V7-I. (D-7 G7 Cmaj)
The idea to make the melodic fragment is to use the 4 notes of the V7.
I III V VII (G, B, D, F) and mix them with the notes of a Maj triad built off of the 6th scale degree of the V7(G7). So an Emaj triad. E, G#, B.