IIm7 - V7
As mentioned with the prgression IIm IIm7 Vsus4 V, the two chords IIm7 and V7 are often the basic element for whole songs or endless intrumental solos (the first records of Carlos Santana are a good example for that). IIm V is also part of numerous chord progressions like the 2-5-1 progression (IIm7 V7 Imaj7, z.B. Dm7 G7 Cmaj7) etc.
Unlike the lection before we will now use the V chord with a seventh. The V7 chord is also called "dominant seventh chord".
This time chord diagrams are only shown in three different keys (C, D and F major), but with quite a few variations. On some of them the root is not the lowest note. You should always know where the root tone is in a chord shape. Then you can easily transpose the chord (progression) to a different key.
For being able to play the IIm7 V7 progression through all 12 keys, it's enough to know just a few of the shown chord variations. Like in the lection before the key changes in steps of fourths, so that the V7 chord becomes the IIm7 chord of the next key. When you start practising, I'd recommend to repeat every IIm7 V7 two times (or even 4 times as shown in the video).
The video demonstrates how the IIm7 V7 progression might be played through all 12 keys.