How do you log your period?

What do you log as your first day and last day? I was logging my spotting and clots as one the time before but someone mentioned it's not considered an actual period flow. So this time around I logged each day where there was a flow...but I'm spotting and having clots the last two days without a flow. In order for the app to track my fertile days correctly do I log these since I more than likely can't conceive when this is going on?