Greetings Wrlfl,
It sounds like you may be trying to sync your content wirelessly, from your PC to your devices. If so, check out the following steps: 
"Sync your device over Wi-Fi
Here are ways to sync wirelessly when your device is on the same Wi-Fi network as your computer (the computer must be turned on):
Should we have an incorrect understanding of the issue, consider offering additional details to help the community guide you to a resolution.
- What exactly is happening vs what you expect to happen.
 - Any error messages you may see.
 - Which iOS version you are using. 
 
We hope this helps resolve the issue with your devices syncing. 
Best wishes.