
Use your DRock account - the same one the app and the headset use. You will see any library shared with you, plus your own PCs.
No account yet? Create one.
Reinstalled a PC? Check its address and last contact, then remove the old server. Removal updates your account on every device.
Opening a library takes you to that PC's own page, where you sign in once more. We deliberately do not carry your sign-in across - see the note in the source.