There is no visual interface for API documentation! The Example 9.21, “API Documentation” explains how it´s being used on a Tcl/Tk source-code file. Place your own API documentation scripts in a tcl-source code file and source it from the »Jeszra;« prompt inside the Jeszra shell window.
It is also possible to make a pseudo project for generating API-documentation. The Example 9.21, “API Documentation” will have to be transformed into ???.