Open Orchist, go to Settings, and choose Connect Apple Music. If nothing happens, check that Orchist is allowed to use Apple Music:
Playing full songs needs an Apple Music subscription.
CarPlay comes with Orchist Pro. Connect your iPhone to the car, then tap the Orchist icon on the car's screen. Only Orchestrations with "Show in CarPlay" turned on appear there, and you can change that in each Orchestration's menu.
Orchist syncs through iCloud. Make sure each device is signed in to the same Apple Account and that iCloud is on for Orchist. New changes usually appear within a minute.
Bought Orchist Pro on another device? Open Settings in Orchist and choose Restore purchase. One purchase covers your iPhone, iPad and Mac, and Family Sharing is included.
Email support@orchist.app with your device, the version of Orchist (in Settings), and what happened. Screenshots help.
Orchist is licensed under Apple's standard End User License Agreement.