One of the first designs of this I have seen, an intentional 15-minute City that is in the heart of Tempe Arizona. They are accepting move-ins this october!
I imagine one could start a non profit organization to collect funds and inform people, then proceed to start building it. The first step is to find people willing to contribute to the project and get together. I’m not very knowledgeable in the matter sorry.
I’m not even sure I like the concept of creating such a place from the ground up as opposed to making the necessary changes (public transit, bicycle roads, etc) to make existing places more livable. The solution proposed here feels like isolating a bunch of rich educated people in a private neighborhood so they can feel good about their life. A better goal would be to allow everyone to access such a lifestyle without rebuilding it all.