File transfers
Depending on what computer you have and what capabilities it has, you may be able to do it via wireless, wired Ethernet, or even USB. The most straightforward way (and the fastest, if you computer has fast Ethernet), is to simply mount the Time Capsule's drive on your computer's desktop, and drag and drop the files.
This assumes you know where the music library is and where it should go.
Mounting a TC drive on a Mac is a simple matter of selecting "Connect to Server" from the Finder's Go menu). If the TC is connected and powered up, you should see it as one of the possible choices.
Hope this helps.
Tom