Open the folder in which you have downloaded the MS office setup and double-click on the setup icon.
It starts the process of installation after when you agree with the terms and conditions of the software.
Click on the submit button after reading the T&C of the software and wait for few time.
After some time click on the finish button of the pop-up window.
For more info please visite:- http://www.ms-setupoffice.com/