Appium has an environment setup procedure for setting up the iPhone Xcode SDK and Android SDK, along with the required simulators and emulators.
The Appium setup instructions are located at http://appium.io.
Of course, Java 8+ must also be installed, as was done for the browser nodes, and the Appium server needs to be installed in the /opt/selenium (macOS and Linux) or C:appium (Windows) directory.
Node.js and npm are also required to install the Appium server, and the procedures are also outlined on the Appium website:
// appium_iphone.sh
/usr/local/bin/node /usr/local/bin/appium --address 127.0.0.1 --port 4723 --session-override -nodeconfig /opt/selenium/iphone_config.json --log-level debug
// appium_android.sh
/usr/local/bin/android-sdk/tools/emulator -avd emulatorName -skin resolution -dns-server 127.0.0.1 &
/usr/local/bin/node /usr/local/bin/appium --address 127.0.0.1 --port 4723 --session-override -nodeconfig /opt/selenium/android_config.json --log-level debug