Install the SSD and Windows disc. Boot from the disc, and instruct Windows to install on the SSD. Under Custom Install it will give you options; you can usually differentiate by size. Install it on the SSD the same as you would on any computer. In BIOS (F2), go to Boot Order and choose to boot from the SSD first.
You say this is a new computer. Have you turned it on at all, run any pre-installed Windows on the HDD? You could run into problems on the install with Microsoft having "safeguards" in place trying to lock it to your one (pre-built?) system, but if all goes well it should be an install (albeit a Custom one) like any other.
Have you put anything on the HDD yet? If not, you can go in, booting from the SSD or a live disc, and just format the drive. That will erase everything, including the current Windows install. If Microsoft tries to get picky about licenses, not having it installed there will help.