There are two sets of examples here, issuers and clients. Issuers are examples of setting up an OpenAuth server. The clients are examples of using OpenAuth in a client application and work with any of the issuer servers.
The fastest way to play around is to use the bun issuer. You can bring it up with:
$ bun run --hot ./issuer/bun/issuer.ts
You might have to install some workspace packages first, run this in the root:
$ bun install
$ cd packages/openauth
$ bun run build
This will bring it up on port 3000. Then try one of the clients - for example the astro one.
$ cd client/astro
$ bun dev
Now visit http://localhost:4321
(the astro app) and experience the auth flow.
Or head over to http://localhost:3000/password/authorize
to try the password flow directly.