Over the years there have been several tools and instructions on how to get the Watchtower Library to run on a Mac. Since it is a Windows application it will not run natively without using some sort of Windows emulator that enables a Windows program to run on the Mac.
With the release of the latest macOS, Catalina, a lot of the previous methods to install and run the Watchtower Library on a Mac stopped working. Since I use a Mac I ran into this issue and had to figure out how to get it working again. I have created a separate page showing the steps to install and run the Watchtower Library on a Mac running macOS Catalina. If you need help with this you can find this page here: Installing Watchtower Library on a Mac with macOS Catalina