"Identifying and authorizing users for GitHub Apps" process unclear

authorizing users for github app 

I have a problem understanding these steps from link above

the say to request   Request a user’s GitHub identity ** I should do 

GET https://github.com/login/oauth/authorize


Q: but who will issue this “GET”??  does the browser do this when installing github app?

Its speaks of parameters

  • client_id

  • redirect_uri

  • state

  • login

Who is constructing the uri? when does this happen, if someone is installing a github app this is the github website, not mine, so how am i supposed to construct this request, since the page is not loaded from my website?

Thanks

jacob

This happens in your application. You can open it with frontend logic, or redirect to it from a server.

I usually create a path on my server <domain>/github/login, which redirects the user to that URL if the session isn’t already authenticated

(edit: just realised I replied to an answer about 18 months after it was posted. Hope this helps someone)