Use npm to install Protractor globally with:
npm install -g protractor
This will install two command line tools, protractor and webdriver-manager. Try running protractor --version to make sure it's working.
The webdriver-manager is a helper tool to easily get an instance of a Selenium Server running. Use it to download the necessary binaries with:
webdriver-manager update
Now start up a server with:
webdriver-manager start
This will start up a Selenium Server and will output a bunch of info logs. Your Protractor test will send requests to this server to control a local browser. Leave this server running throughout the tutorial. You can see information about the status of the server at http://localhost:4444/wd/hub.
protractor conf.js