If you were on a free Brewster account, you will first need to import your contacts from Brewster into your FullContact account. Afterward, we suggest connecting your Google Contacts account(s) and setting them to Sync with your Unified Contacts. You will connect your Google Contacts account on the same page that you imported your CSV file of contacts from Brewster: the Address Books page. After doing so, bi-directional sync will be enabled.
However, keep in mind that FullContact's software only bi-directionally syncs with your My Contacts in Google. Therefore, if you were on a Premium Brewster subscription, Brewster synced with both your Other Contacts and your My Contacts in Google However, keep in mind that FullContact only bi-directionally syncs with your My Contacts list in Google.