To create a new list entry, open the list you want to add and press a New activity on left bottom corner > New. For example, to add a new billing rate level, open Billing Rate Level List and select Billing Rate > New. A new dialog box appears to allow you to add/create a new billing rate:
You can create a new list in other lists above in the same way: open the List and select the New activity in the corresponding list.
To modify or edit the list, open the window for that list, then select the entry you want to edit and select activity > Edit or double-click the entry to open its dialog box:
When the dialog box is opened, you can then make the changes you want and click OK once you are done.