It can be a relief to discover how very simple and straightforward it is to play the piano spontaneously - improvising. Here are several video clips demonstrating different improvisation techniques.
Anyone can Improvise, published by Informance, includes downloadable text and examples.
For further clips, please visit https://online-academy.informance.biz/online-academy/5-anyone-can-improvise
Understanding chords and how to hamonise
Easy Improvising with the White-note Modes and Other Exotic Scales