What are SSHD's
Are you wanting to install Windows 7 on a Solid State Drive (SSD)? If thats what you want to do and you do not want to put any thing on your Hard Disk Drive (HDD) then disconnect you computer from the wall power. Then unplugs the wires to your HDD plug the power back in and and do the install. if you want to use your HDD after the install unplug the power again and reconnect the HDD.
IF you want to do something else please explain what you want to do.