Once you’ve connected the two then all your new workouts will be swooshed on over to Strava. Check that workouts without GPS go across as well. Sometimes they don’t. [Edit:an indoor pool swim workout went across to STRAVA but an indoor gym workout did not…figure that out]
The transfer will probably be a basic TCX-like transfer, so just the basis laps and stats go across, nothing fancy like HRV (probably)
You can also export old efforts directly to strava as well. Cool
As the press release says, the privacy setting from Flow are passed to Strava. So if you want strava to be private set up Flow in the same way.