Steps:
- Audit your existing content (e.g., manuals, guides) and break it into reusable chunks (topics).
- Identify duplicative or redundant content to reuse.
- Transform your content into the DITA XML format with utilities such as DITA Migration Tools or oXygen XML Editor.
- Make a DITA Map to link and organize your topics hierarchically.

Tools: oXygen XML, XMetaL, or Adobe FrameMaker.