I guess it’s possible that it might say ‘0’ in the box highlighted below until you take a test or manually enter a value in your profile:
But there is some default (calculated) value in workout mode. I think the ‘default’ FTP value is different for everyone (probably calculated based on age/weight/gender info that you provide when you create your account). If I remember correctly, I think mine was set to 175 W on day 1 (which, for me, worked out to ~ 2.6 w/kg at that time). You would have been able to see what that value was by looking at the slider position on the right side of the Training window, here (set to 220W):
Now that you’ve changed it using your own esitmate? There’s no way to go back and see what you were using when the workouts were ‘hard’.
In any case, it doesn’t matter now. You should just take one of the FTP tests (after properly calibrating your trainer) to find out what your FTP really is. THEN start the FTP builder workouts. Beginning any training plan w/o reasonably accurate knowledge of your current FTP is somewhat self-defeating.