When VBdocman is set properly, you can compile a new documentation.
Go to Add-Ins -> VBdocman menu or press VBdocman button on standard toolbar.
Options dialog appears.
Check Non-commented option, if you haven't used VBdocman comments, so that all specified objects were compiled using default comments. Press Compile button. Compilation progress dialog pops up and some log messages are printed in it.
Note, longer projects can take a little while to compile. You can stop compiling by Cancel button. After compiling press Close button or you can test generated documentation by pressing Show Documentation button.
You can also compile your whole project group at once by pressing Compile Group button. More info in Compiling Documentation for Project Group.