Adding & Removing Entries.
Within each group, you can add entries. Entries are the smallest parts of a Wallet database, storing bits of data such as passwords or credit cards. You should only have one entry per piece of data. (i.e. one entry for your MobileMe account info, one for your Flickr account).
Creating a new entry.
To make a new entry, select the group you want the entry to go under, and click the "+" button under the entries list. Or, go to File>New Entry.
Removing an entry.
Removing entries is very simple. Simply click the "-" button or hit the delete key when an entry is selected. You can also select multiple entries to have them deleted. By default, Wallet will not ask you if you want to delete an entry before doing so. You can change this in the Preferences.