How do I reset my iPhone back to factory conditions?

Turn on computer, open iTunes, connect iPhone, click restore, choose as new when given the option

the iphones comes with a cable where there is an usb connector in the other end

and that connects to the usb port of the computer

nabila186 wrote:

Sorry, how do I connect my iPhone to this?

Plug one end of the cable to your computer and the other to your iPhone.

You should really read the manual. Click Support at the top of this page, then iPhone for access to the manual