As you can read in http://appium.io/ Appium is an open source test automation framework for use with native, hybrid and mobile web apps. It drives iOS, Android, and Windows apps using the WebDriver protocol. So if you are trying to automate tests for a mobile app, this is a tool you must check.
To install Appium Desktop (server side) you must download the corresponding binary from https://github.com/appium/appium-desktop/releases/ There is a
.dmg for your Mac, a
.exe for your Windows or a
.AppImage for Linux. Take into account in Linux you must run
chmod a+x to grant execution permissions, and run
./AppImage to execute it.
If you are interested in automating Android apps, you have to install Android Studio, Android SDK (can be easily installed during Android Studio installation) and Java (remember to set JAVA_HOME).