Within WeOpportunity you can add/edit/disable data list items.
To do this:
Go to Settings -> Data List
Select the Data List you are looking to add to and click "Add New Record"
Similar to Adding you can remove a data list by clicking delete.
The delete function however will not work if there are any existing leads with the data list item already selected.
In this case you can deactivate the data list item by unchecking the "Active" checkbox.