Login to your Jcow website as admin, go to Admin CP -> Modules, Enable Facebook Connect module
Go to https://developers.facebook.com/apps/, Click "Create App" button, "App type" select "none".
Once App created, you will be redirected to your app dashboard. Click the "Set up" under "Facebook Login". Ignore the "Quick start".
Click the "settings" under the "Facebook login"
In the "Valid OAuth Redirect URIs" section, input the following URL (Replace the YOUR_SITE_URL to your own website url):
https://YOUR_SITE_URL/index.php?p=fblogin&act=verify===
In the Facebook App page, click "basic" under "settings" section, you will get App ID and Secret. Copy them.
Go to your Jcow website, click "Admin CP" from sidebar, scroll down and click "Facebook connection settings", then paste the Facebook app ID and Secret and click "Save".