I actually tried two ways:
1. I tried to get b4j-bridge working. I put jdk-14.0.2.jdk in /libray/java/javaVirtualMachine but I did not know what to do with javafx folders. I tried putting the javafx folders in the same directory. I got the b4j-bridge working but when I ran my program, I got the error:
Error: JavaFX runtime components are missing, and are required to run this application
At that point, I abandoned that approach.
2. Next, I tried using the MacSigner. The error code was generated after I hit the "Link" button and running it using "run.command"