1. We started by writing down treble and bass clefs and 3/4 meter and prepare 12 empty measures:
We have repeated the opening chords (C-Eb) during the introduction, in Codetta - the last two (E-F#) and everything closed with the C major chord and the 13th measure.
I think that what we came up with is interesting enough. If you are of the curious type, you too can try creating something like that.
PS The same 8 or 9 steps would have to be applied in learning to improvise such a piece (the bass part could be played with pedals).