How to install windows 7 in laptop

How to install windows 7 in dell inspiron 15 i3 laptop??

1. Enter your computer's BIOS. ...
2. Find your BIOS's boot options menu. ...
3. Select the CD-ROM drive as the first boot device of your computer. ...
4. Save the changes of the settings. ...
5. Shut off your computer. ...
6. Power on the PC and the insert the Windows 7 disc into your CD/DVD drive.
7. Start your computer from the disc

see more in video bellow