How to adapt one to the other: Whenever the guiding narration says to rest my focus on the rhythm of the breath, I rest my focus on the rhythm of walking instead. That's it! The rest of the practice is entirely the same.
I've been doing Headspace Pro recently, which is unthemed and includes long periods of silence. Nearly every afternoon, ideally after eating lunch and before the sun gets too low, I go to the little park down the street and walk for 20 minutes or so, very lightly guided by the minimal narration, experiencing the park and the change of seasons and the people and animals that pass by. It's just lovely. I dropped the practice in the summer, because I don't need a reason to get out and walk--I do plenty of it without even trying--and my schedule is often so packed that it's hard to find even 15 or 20 minutes for myself. I expect I'll drop it again next summer for much the same reasons. But I'm so glad to have it for the fall and winter and spring, and I hope to bring FutureKid along with me on many future walks (without headphones in, obvs).
Today I started reading Thích Nhất Hạnh's The Miracle of Mindfulness. I was looking for his book on walking meditation and couldn't find it, but this was sitting right there (we actually owned two copies). It feels like something I would have nodded along with in the past, but not really viscerally understood. Now that I have an actual meditation practice to link it to, I think I'll get more out of it. In the meantime, it's just enjoyable to read. And it feels so validating to read things like this that both echo my experience and provide gentle direction:
When you are walking along a path leading into a village, you can practice mindfulness. Walking along a dirt path, surrounded by patches of green grass, if you practice mindfulness you will experience that path, the path leading into the village. You practice by keeping this one thought alive: "I'm walking along the path leading into the village." Whether it's sunny or rainy, whether the path is dry or wet, you keep that one thought, but not just repeating it like a machine, over and over again. Machine thinking is the opposite of mindfulness. If we're really engaged in mindfulness while walking along the path to the village, then we will consider the act of each step we take as an infinite wonder, and a joy will open our hearts like a flower, enabling us to enter the world of reality.
I like to walk alone on country paths, rice plants and wild grasses on both sides, putting each foot down on the earth in mindfulness, knowing that I walk on the wondrous earth. In such moments, existence is a miraculous and mysterious reality. People usually consider walking on water or in thin air a miracle. But I think the real miracle is not to walk either on water or in thin air, but to walk on earth.