Please install these tools to be ready:

• Chrome https://www.google.com/intl/en/chrome/browser/
• Node.js http://nodejs.org/download/
• angular-cli $ npm i -g @angular/cli
• IDE / Editor I Highly recommend vscode https://code.visualstudio.com/Download

Test:

node -v
npm -v
ng v

hint

Clean up old version (if installed)

npm unlink angular-cli 
npm rm -g angular-cli 
npm cache clear

or in case of other problems while install angular cli 

npm unlink @angular/cli 
npm rm -g @angular/cli 
npm cache clear