How to add "users" to your bot?

An “app” is the program in your wording, it would seem.
The program will connect to chat as a user.
So it uses a user token, since it needs to operate as a user.

The App Access Token is only useful for accessing public data and cannot be used to write. (Using chat is write)

You used implicit auth instead of regular code auth.
Should be using the latter for most applications/programs.

Are we talking about getting the bot auth token.
Or the flow to let users sign up to use your bot.

This looks like the latter.

Either way:

  1. Create a web page that has a <a href=""> link to Twitch oAuth
  2. User clicks that link
  3. The accept (or decline) the link
  4. They come back to your website with a ?code
  5. Back end grabs the ?code and exchanges it for a token and refresh token.
  6. User is now logged into your website essentially.

No.

Since your bot is logging into chat as the bot and not as every other user

The chat join command doesn’t need the token just the user name.

Bot logged in as fred
Alice logs into your website and hits the join button
Website tells bot to do a thing
Bot then sends /join #alice