That menu is not updated, so indeed you can't find the Character Generator Map there. So you have to do as did, go into the map list on the left side of the software and select it there.
As for the Scene not being opened, it should open. So let's first test only on the sample project. After we manage to make it work on the sample project, then we move on to your personal project.
1 - Get the downloaded file EliMZ_CharacterGeneratorPro.js and put it inside the js/plugins folder.
2 - Open the plugin manager and enable, set the Character Generator to ON.
3 - Go into the map, and test it.
If you did everything above and it did not work on the sample project, send me screenshots of the process:
A - Of the plugin file inside the JS folder of the sample project.
B - The plugin manager with the Character Generator set to ON.