You can leverage all the data you send Sift when building Lists and Workflows, or doing one-time searches.
To edit a list, just click on the Criteria.
In the criteria builder, you will see Categories on the left hand side which help you filter through all the potential items you can use. On the right side are the actual items you can choose from. Hovering over any item on the right will expand to display a full description.
Once you've selected an item, you'll be taken to a screen with a full description of the item, an area for you to determine its value, and also a hint on how to format your entry.
Once you've entered all the values you desire, click "Add Criteria" to save it to your List.
Notes on Formatting
There are a few different type of fields that require different input types.
3. Text Field -- Note: this field is case-sensitive.
4. Custom fields -- Check with your developer to confirm the possible values and proper formatting. The Activity section of users with these fields will give you a clue as well.