@Override
	public boolean apply(NewSessionData data) {

		if (data.getSourceProgram() == null) {
			Program program = openSourceProgram(data.getSourceFile());
			if (program == null) {
				return false;
			}
			data.setSourceProgram(program);
		}

		if (data.getDestinationProgram() == null) {
			Program program = openDestinationProgram(data.getDestinationFile());
			if (program == null) {
				return false;
			}
			data.setDestinationProgram(program);
		}
		return true;
	}
Wizard step in the new version tracking session wizard for choosing which programs to 
track and naming the session.
Ghidra/Features/VersionTracking/src/main/java/ghidra/feature/vt/gui/wizard/session/SessionConfigurationStep.java