Hi Roger. Welcome to justanswer
Who said it is not supported by your Mac system It is very well supported. If you want me to setup for you then please choose Remote desktop Assistance so that I can set your printer on your system
Once you click this link below(CLICK HERE)A file will automatically get downloaded. Check your download section, a file named ELSINORE.SCREENCONNECT will be present. Just open that file so that I can connect to your computer.
Are you getting any error?
Click this link
Press I Agree and then check the download
Press Apple menu > System Preferences, then click Security & Privacy. Click the “Open Anyway” button on the Security pane of System Preferences.
Or choose Anywhere in the System preferences as shown in this attached image