Hello triboiler,
Welcome to the Apple Support Communities!
From what I understand, it sounds like you would like to add music already on your computer to iTunes. To move your content into iTunes, please follow the instructions located in the attached article.
Adding music and other content to iTunes - Apple Support
Adding content on your computer to iTunes
iTunes helps you add digital audio and video files on your computer directly to your iTunes library. You can add audio files that are in AAC, MP3, WAV, AIFF, Apple Lossless, or Audible.com (.aa) format. If you have unprotected WMA content, iTunes for Windows can convert these files to one of these formats. You can also add video content in QuickTime or MPEG-4 format to iTunes. To learn how to add these files to iTunes follow the steps below.
- Open iTunes
- From the File menu, choose one of the following choices:
- Mac
Add to Library
- Windows
- Add File to Library
- Add Folder to Library
- Navigate to and select the file or folder that you want to add
If iTunes is set to "Copy files to the iTunes Music folder when adding to library," iTunes will copy all content that is added to the iTunes library to the iTunes Music folder. To adjust this setting or change the location of this folder, go to the Advanced tab in iTunes Preferences.
Have a great day,
Joe