Just right-click a local backup you want to e-mail at the Backups tab and select the ""Export by E-mail" feature in the context menu.

The first time you send a backup by email you'll have to fill in your e-mail account info. The meaning and values of the fields are  just the same as the properties of your e-mail account in your mail client application (Outlook Express, the Bat, etc., whatever is installed on your computer). You could just open that software and copy-paste the values of the corresponding fields.