I believe that the integration goes live on 2015-07-22.
You need to mark a segment as a favorite in Strava and enable Strava segments in Garmin Connect.
You will also need an Edge with a software build that supports Strava segments.
I have an Edge 520 so that shouldn't be the problem. Where in Garmin Connect do I enable Strava segments? I don't see this as an option anywhere.
Thanks.
On the left, click the three horizontal bars -> Segments -> add the Strava widget to your Dashboard
On the left, click the three horizontal bars -> Segments -> add the Strava widget to your Dashboard