Cannot add Spotify or figure out the required update on Garmin Express

Trying to set up my new 945 and install Spotify.  However when trying to download via the Connect store I am being told to get the latest version of this app I must update the watch in Garmin Express.  I have added Garmin Express to my Mac and connected thew phone...made an update for maps (the only visible I can see) but can't find anywhere to make the necessary update.  Can anyone help ?  Many thanks