You can watch a video on How to Log a Meal here:

Option A: Add a meal from your list of meal templates.  To do this, simply drag-and-drop the meal from your meal library to the calendar. 

Option B: Create a meal directly on the calendar.  Once you do this, you can choose to save the meal to your library for when you need to add it again in the future (and therefore, being able to use Option A above, a faster and more efficient way of adding meals to the calendar)

Instructions on Option B, Creating a Meal on your Calendar:

1. Click on the calendar day and select "add new meal". 
   
2. Select the meal type and give the meal a name...click "OK"
   
3. You are now in the Quick View for this meal.  At this point you can manually enter nutrition information for the meal.  Or you can click the "Foods (Add or Edit in detailed view)" link to add the foods that make up your meal (recommended).
   
   
   
   
4. Once you click the "Foods" link you will be in the the detailed view.  From here you can drag and drop foods to your meal.  To do this, make sure you are viewing the "Foods" template in the nutrition section, and then select the library from where you want to pull food.  It's a best practice to save frequently consumed foods to your "Favorite" library, but if you need to search for a food you can do that with the other libraries listed. 
   
   
   
   
5. Once you have added all the foods that made up the meal, click the "Save" button.  If you want to save this meal to your meal library, therefore creating a meal template, click "Tools....save to library".

Some things to note: You can change the quantity of the foods that you add by just deleting the current quantity amount and typing in the correct amount.  This will update the nutritional content.  For example, if you add bread but the quantity is 1 slice, you can make that 2.  Another tip: if you need to create a meal that is similar to a meal template, you can add that meal template to your calendar and then add/remove foods from the detailed view.  Let's say you have a lunch planned but did not have cheese on your sandwich.  You can either make that quantity '0' or you can click the 'x' next to the food and take it off the meal.  Editing a meal on the calendar will NOT change the original meal template.