To automatically add all new email contacts to your contact list:

1. Click Preferences at the top.
2. Click Contacts on the left.
3. Here you can toggle the option to automatically Add new contacts to Emailed Contacts.

Other methods of adding contacts:

1. Right-click an email address or name to be able to either Add to contacts or Edit Contact.
2. Click on Contacts at the top, and then click New Contact.

How to edit your current contact list:

1. Click on Contacts at the top.
2. Right-click on the desired contact and click Edit Contact or double-click a contact.
3. Click Save at the top left once the edits are complete.