If you want to go in-depth into the topic, the main book to read first is “Flow: The Psychology of Optimal Experience” by Mihaly Csikszentmihalyi. Here's a detailed page on Flow (and where I sourced this image from!).
Stillness in Motion, Freedom in Focus
One of the most beautiful and paradoxical qualities of creative flow is the way it brings stillness in motion. On the surface, we may be moving, for example, our hands may be painting, our body dancing, our fingers typing, but inwardly, there’s a centred-ness and stillness. This is mindfulness in action. Where we are no longer split between past, future, and a thousand
micro-decisions. We are simply here, in the moment, in sync with the task, not wrestling with ourselves and our surroundings. The usual inner chatter; self-doubt, comparison, planning, melts into the background, leaving only a meditative presence.
How to get into a state of flow
As lovely as it is to be in a flow state, I have noticed that it is not always easy to cross the threshold into it. Often, the first few moments of starting a creative activity can feel uncomfortable,
awkward, even frustrating. This is normal, it is the threshold between scattered attention and deep focus, like a kind of creative turbulence before takeoff.