Spotify SDK Login Button

Hi everybody, I am working on a project for school where we are implementing spotify’s sdk in order to pull songs and playlists from users accounts. We are still in the beginning stages of our project, and are struggling with setting up the login button to connect the users account to their existing spotify account. If anyone has any experience working with spotifys SDK, please share any helpful videos/git links that are related to this. So far after working through spotifys SDK, we are having the most issues with the token swap setup.
Thanks for your help!