To Add Categories in the Calendar follow these steps
*you must be in edit mode
Click on the pencil and select "Edit Categories" from the drop down menu
Give the Category a Name
Click the Down Arrow to choose Background Color
Click the Down Arrow to choose a Font Color
Click Add to finish
To Edit Categories
Select the Category you want to edit from list
Make changes and click Update
To remove a Category click the trashcan next to it and select yes to delete