account linking question

[cAstraea]

Can someone post this full working example of Peter's Hats please :( tried all sorts of combinations and read and reread the messenger-platform documentation https://developers.facebook.com/docs/messenger-platform/account-linking for the past 50 hours it just isn't clear how to do this. The only semi relevant thing regarding this process I could find on the vast internets was this article which didn't seem to work anymore http://espeo.eu/blog/user-permissions-messenger-bots/

Can this auth backend run on another server ? I tried running it in an express + passport on my localhost. Got a button to link the login , managed to see the window asking for permission but couldn't get rid of the window that opens.

where should i redirect the user ? is it possible to login without a webview?
// router.get('/login/facebook/callback',
// passport.authenticate('facebook', {
// successRedirect: 'server/views/closeWindow.html',
// failureRedirect: '/'
// })
// );