Good OAuth approach (?)

Because the user is redirected to a page on my EBS on authentication, which is used for signing in and such, not first time setups.

I should not perform any first time setup just because a user signed in through Twitch, instead I fetch the tokens and call another endpoint with them as parameters.

I could probably get the ”code” parameter instead and pass that as a parameter to the first time setup endpoint, which then would get the tokens.