To install windows XP you need to have CD of Windows XP.
After that you need to make sure that in your BIOS the first boot sequence should be CD ROM.
Third step will be to insert the CD in CD ROM. And then just turn on your PC or laptop.
Once your PC start .it will prompt you to boot from CD ROM . you need to press enter key.
After checking your PC configuration it will ask for creating partition in your HDD.
You can allocate partition as per your choice.
Remember you can prss C to create and D to delete partition.
After that you need to fill in product key.
And then follow the steps.
And now you are ready to go.