Make sure to disable updates for iptv manager or it will install the kodi repo version over top since it is a version ahead currently
Open the Sling TV addon it will prompt you to login to your account or select Stream Free
Once you've logged in successfully go to IPTV Manager Settings and select Refresh channels and guide now
It's recommended that you set the Refresh interval in IPTV Manager to 12 hours (or lower) since guide data is 24 hr period this will prevent any gaps in the guide