I found this after 10 seconds on google search, which seems to explain everything you want to know, and yet more:
A little-known feature in Evolution is the ability to synchronize your Evolution Contacts with Gmail's Address Book. This is a great way to get your contacts offline and still synchronized with Gmail. To set this up, go to Contacts and click File -> New -> Address Book. Change the Type to Google, give it a name, put in your username (without the @gmail.com), and optionally select SSL. Click Apply, and all your Gmail contacts should show up in Evolution's Address Book under Google -> addressbookname.