Level 1: Enable web sign-in
Link your website with a rel=me link to a common OAuth provider such as Github or Twitter. Or you can put your email address or phone number on your site to use Persona or SMS-based authentication.
Find or create an authorization server and tell IndieAuth clients to use it when signing in.
Link to it from your homepage as follows:
<link rel="authorization_endpoint" href="https://indieauth.com/auth">
Level 3: Use other IndieWeb apps
Use a token endpoint service
Such as https://tokens.indieauth.com
Create your own token endpoint
Create your micropub endpoint
Sites that support distributed IndieAuth