Session time is the time for which a Guest is given access after login. The landing page is not shown to the guest for the duration of a session even if he disconnects and connect.
After logging to Spotipo dashboard, select the site you want the configuration to apply
Now go to the Settings and select the Authentication tab
Press the Config button next to the login method you want to configure and go to the Session Control tab
Set a time in minutes here, please note that Restrict Sessions is set to No Limit, this means guests will be able to re-login after the session expires.