The heart of the lies in the O/Dev module, the 2D pattern design system. This section of the documentation is the thickest and most referenced. It teaches the fundamental language of the software.
If you have a current support contract with Lectra (which owns Optitex), log into the portal. Under the "Documentation" tab, you will find: optitex manual
: Contains essential tools for drafting, including the "Point" tool for shaping and the "Draft" tool for creating new segments. The heart of the lies in the O/Dev