The circle of 5ths is quite a simple yet interesting concept in terms of chord progressions. It is interesting because the keys change frequently but the chords do have a common relationship. In every key you will find two Major chords, then 1 and the 5, so for example the key of C Major has Cmaj and Gmaj as major chords. Now when you think about it, Gmaj is also the first chord in the key of G, the 5th chord is Dmaj and so on.
Is it very easy to visualize this on the piano because you simply just observe which finger is on the 5th key use that for your next major chord.
The below example shows how C major is made up from 1, 3 and 5. The next chord in the circle would be G major (starting from 5) and so on.
Incidentally, also not the the minor chords on the inside of the diagram represent the minor equivalents. Once you learn all 12 major scales, you should also know the minor scales and can refer to them using the above diagram.
This will allow you to expand your chords while freestyling and can also give your music more of a gospel sound. Check out the video below.