1) install brew
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
2) with brew install npm
brew install node # get node.js
3) with npm install appium (terminal version)
npm install -g appium # get appium
npm install wd # get appium client
appium & # start appium
for Appium GUI version - just download dmg file and install as usual.