Hi Steve,
Hope you are well !!
From your active Logform, click on "Log" in the upper left corner (to the left of "Voice Keyer", "Terminal" and "CW Keyer"), then "Setup", that will open the Log form setup window, click on the tab "Auto ADIF Logging" in the upper right corner. Assuming your running a single instance of WSJT-X just click on the "WSJT-X" button and it will enter the default filepath, otherwise click on "Select" and manually navigate to the location of your specific WSJT-X Adif log file.
I can post a pic if needed, just scream, otherwise let us know how it went.
73 de Brad, N8GLS