Installing: Javelin3 is an application provided by an Apple approved developer, Drumlin Security. If you have a warning message from Apple regarding the app security then check your SETTINGS facility (the cogwheel icon in the screenshot below) and select the "Security and Privacy" facility, General tab, and you will see you can allow apps downloaded from: "Appstore and identified developers" - so that should solve the problem.
When Javelin3 for Mac is run an icon for the program will appear at the bottom of the Mac window and a menu of functions at the top left of your screen. If the menu is not visible click on the program icon at the bottom of the screen and the menu should then appear at the top left
The Javelin3 menu bar, File menu, will include an entry marked CATALOGS for most recent versions of OSX (10.12.4 onward) - if there is no CATALOG entry, as in the example illustrated, drmz files must be downloaded directly via the built-in Download facility or via Safari or other file transfer facilities.
Documentation: Help documentation is available online here
Common issues (e.g. printing, network problems etc. - please see the Help on common issues page