Find out where your Appium installation is: $ which appium /path/where/installed/bin/appium
Given this installation location, /path/where/installed/bin/appium, WebDriverAgent will be found in /path/where/installed/lib/node_modules/appium/node_modules/appium-xcuitest-driver/WebDriverAgent. Open a terminal and go to that location, then run the following in order to set the project up: mkdir -p Resources/WebDriverAgent.bundle ./Scripts/bootstrap.sh -d