hmmmmmmmm press button, raise hands slightly in air, wait for beep, if no beep place hands over face and say "what have I done". If beep continue holding that position, wait a moment, if a screen comes on raise hands above your head and say "success!", if not place hands over face and say "what have I done?"
ok I'm being a smart ***, but heres what you do double check everything one last time before you throw the power to it. The hit the button, and hopefully it'll beep once and goto the memory test screen, where it will tell you to hit del(or some other key) to go into the bios. Go into the bios, change the boot sequence to read the cddrive first, put your winxp disk in the cddrive, then save and exit. Then if all goes well xp setup will start and you'll have to partition and format the drive. At some point in the setup it will want to reboot, change the boot sequence back to the Harddrive, save and exit, and let xp setup continue.
Thats a greatly shortened version, but its not too complex. Unless your installing on sata drives, then you first have to make a floppy with the sata drivers supplied with your motherboard