Regular workouts or non-race activities can be saved into your workout library as an unstructured workout, allowing you to easily drop these activities into your calendar and account for them in total training time and expected training score. 

To create an unstructured workout, click the add template workout button from the workouts side bar:

Enter in the title and other details, then when selecting save, choose unstructured workout from the drop down. Once you've selected this option, the distance, duration, and t-score options will pop up and allow you to fill in these details manually. After these items are filled in, hit save and close out of the workout. It will now live on your workouts side bar under "Mine".