Use Apple Watch to control music on a Mac or PC
Use the Remote app 
on your Apple Watch to play music on a computer that’s on the same Wi-Fi network.
Add a music library
Open the Remote app
on your Apple Watch.Tap Add Device.
If you’re using the Music app on a Mac with macOS Catalina or later: Open Apple Music and select your device from the list of devices shown with your library.
If you’re using iTunes on your Mac or PC: Click the Remote button near the top left of the iTunes window.
Enter the 4-digit code displayed on your Apple Watch.
Control playback from Apple Watch
Use the playback controls in the Remote app . Turn the Digital Crown to adjust volume.
Choose a media library to play from
If you added more than one library: Tap the one you want when you open the Remote app
on your Apple Watch.If you’re already playing music: Tap
at the top left of the playback controls, then tap the library.
Remove a media library
Open the Remote app
on your Apple Watch.Firmly press the display, then tap Edit.
When the device icons jiggle, tap X on the one you want to remove, tap Remove, then tap
.If that was your only remote device, you’re finished—otherwise, tap
to finish editing.