How do I use/link javafx to run applications?

I'm trying to run a non-Trisquel package I installed with dpkg. I don't much about java. I installed a .deb, couldn't find the executable, then found jar files with the package name in /opt.

java -jar trainchineseDesktop.jar

gives me the error

Error: JavaFX runtime components are missing, and are required to run this application

openjfx is installed but I don't know how to make it visible to the program.