Hey Brian! I would start with checking your account to be sure you have Keyword Tracking numbers set up to pull in keyword level data - source trackers do not provide this level of data.
Once you have your keyword pool created, the next step is checking to be sure you have added keyword parameters in your AdWords account to send call data to CallRail (otherwise CallRail won’t have permission to receive those keyword details).
This article includes instructions for how to add the keyword parameter in your Google account: https://support.callrail.com/hc/en-us/articles/202672388-How-to-View-Keyword-Data-for-Google-AdWords-Calls-in-CallRail-.
It takes 24-48 hours to populate after that so don’t be concerned if you do not see the keywords call data show up immediately. Let me know if that helps!