# Working with Precedence Units

To create custom content, you will first need to create a precedence hierarchy in the Admin Tool. The Admin Tool edits the Organizations.xml file and constructs the file system folder structure where the content will be stored. When the repository is built, the custom content will be included in the build.

- Add a Custom Precedence Unit
  The following steps describe how to open a repository so you can add a new precedence unit or delete any obsolete units:
- Remove a Precedence Unit
  When you no longer need a precedence unit, it may be removed using the Admin Tool.

Parent topic: Expere Knowledge Base Repository