Postman is a chrome app. So it runs on chrome browser. So, before running postman you must install Google chrome. Here is the Google chrome link. http://www.google.com/chrome/
Now let’s install postman step by step. It is very easy.
Step 1: Type following URL and press enter
Step 2: Click ADD TO CHROME
Step 3: Click App
What we actually do here we installed postman REST client and then consume github api.