How do I record a Symptom after-the-fact?

From the Home screen in the FCV Sentinel app, click the "Enter Symptoms" button. In the resulting screen select the specific symptom from the "Symptom" dropdown. 

Once the selection is made, you'll note that you can drag the "Severity Scale" slider to the appropriate place between the "Low" and "High" severity boundaries. Since you're entering a symptom that you experienced in the past, click the "Enter Time" button and select the time you experienced it via the prompts, then finish by pressing the "Save" button at the bottom of the screen.