I cannot find path to Chimera.jar

You can select path to java and Chimera.jar to configure IDE to run Chimera. The path information is stored in a special file. In windows it is stored in the registry under
and under unix is seems the info is stored within a file in the users home directory called .chimerapath.

Take a look at the QxRunDialog.cpp files for studio QxRunDialog::OnConfigureChimera