diff --git a/doc/gerrit.rst b/doc/gerrit.rst
index 49a74d3b..ff80c17a 100644
--- a/doc/gerrit.rst
+++ b/doc/gerrit.rst
@@ -389,7 +389,11 @@ Depends
 Keys
 ====
 
-The key for the launchpad sync user is in ~/.ssh/launchpad_rsa.
+The key for the launchpad sync user is in ~/.ssh/launchpad_rsa. Connecting
+to Launchpad requires oauth authentication - so the first time
+sync_launchpad_gerrit.py is run, it will display a URL. Open this URL in a
+browser and log in to launchpad as the hudson-openstack user. Subsequent
+runs with cache the credentials.
 
 Running
 =======