You get 2 stops plus a final destination on any international reward. If you choose, you can replace one of those stops with an open-jaw that either begins or ends at the destination. If that's the case you fly:
Home - City 1
City 2 (Destination) - City 3
City 3 - Home

Without an open jaw, it would look like:
Home - City 1
City 1 - City 2 (Destination)
City 2 - City 3
City 3 - Home

Mark