Home & student Installation steps
1) Open browser Google Chrome
/ Internet Explorer ,Go to www.office.com/setup
2) Sign in with your Microsoft account (e.g. Hotmail, outlook or live) or create a new Microsoft account incase if you do not have any (https://login.live.com/)
3) Enter the 25-character product key you have received via Email/Courier.
4) On confirmation of Key activation, Click Next and proceed with onscreen instruction.
5) click on Services & subscription on top 1st line in your office.com account.
6) See your office Home & Student registration and Click on Install link besides the product name to start downloading the product installer.
7) Run the installer from your download folder and follow the instructions.
8) Once the 100% installation is completed, Restart your PC.
9) open word/ excel or powerpoint to check the application.
10) in future whenever required only put the Registered email and password as verification and product activation.
11) Note: Product key registration will happen only once after the key is registered. Customer has to remember and put registered Email id and password.
Reference links :