It is also possible to use CalenGoo on Linux but due to the many different Linux systems it won’t be supported on all systems. You have to check if it works and if you have problems you can ask questions in the forum.
CalenGoo requires Java 1.8 and JavaFX. The best is to download and install the Oracle JRE or JDK e.g. from here: http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

An alternative is to install OpenJDK, but then you cannot watch the tutorial videos and alerts display only a single line of text. E.g. on an Ubuntu 17 system you can install OpenJDK this way:

sudo apt install default-jre
sudo apt install openjfx

Then download and unzip CalenGoo-Java.zip and start it using the file "calengoo.sh".