If Covve is linked to Gmail or Outlook / Exchange
To use your Facebook contacts with Covve you can export them from Facebook and import them into the address book that you have linked with Covve (gMail or Outlook). These will synchronize with Covve.
Facebook doesn't support export of your friends list. There are however a couple of workarounds:
a) If you have (or want to create) a Yahoo! account you can use the technique described here
b) Alternatively there are some Facebook Apps that enable you to export your friends. You can search for these on Facebook.
Instructions on how to import your contacts can be found:
a) Here for Gmail
b) Here for Exchange/Outlook
c) Here for Office365
If Covve is linked to your iPhone
Alternatively, if Covve is linked to your iPhone you can add Facebook to your iPhone contacts and this will in turn synchronize them with Covve.