A chord progression is a series of chords put together in a pattern. In the beginning of the video, I play a chord progression in the key of F. That progression is F, B flat, C, B Flat, and back to F.
Chord progressions are based around piano scales , so when I say the song is in the key of F, I mean that its chords are based on the F major scale. F is the root of the scale, B flat is the fourth note of the scale and C is the fifth note of the chord. Because of this we can say that F is the I chord, B flat is the IV chord, and C is the V chord. These three chords are the most popular chords in modern music. A lot of the songs you hear on the radio are written with just those three chords, although in a variety of keys.
Play around with the chords on your keyboard. You can put them in any order you like. For variety you can pick out individual notes of the chord instead of playing the whole thing at once. You can also play around with the pattern in which you play those individual notes of the chords, or play around with different inversions.
Let's build a different set of chords from a new key to help you fully grasp the concept. I'm going to use the key of E major. The root of the E major scale is E. Next let's hit the II chord, based on the second note of the scale, F sharp minor. From there let's play the V chord, a B chord. Now let's return to the E chord for a couple of measures. Another chord we haven't used yet is the VI chord. The sixth note of the E major scale is a C sharp, so let's play a measure with a C sharp chord. From there let's go to the IV chord, which is an A chord, to the V chord, back to the root chord of E.
You can see that we've used a variety of chords in that last performance, but all of them are based on the scale of the key that the song is in. There are several common, formulaic, chord progressions, but if you play around with chords and get a feel for how they sound together, you'll be able to create your own custom chord progressions.
To figure out more chords, you can study the Circle of Fifths .