+1 on only connecting the SSD, leave the HDD unconnected at first.
Getting into BIOS is done by pressing a certain key at the logo screen when the PC is switched on, most of the time it's the Del-key, but on the logo screen can mention that it's another key, like F1 or F2.
Once you get the BIOS screen, you normally don't have the change anything, normally the optical drive is set to boot priority over the HDD, but even if it isn't, as there is nothing on your HDD, it will still boot from the DVD drive. Just put the Windoze DVD in the drive after powering up the system, and hit Crtl-Alt-Del for the system to restart and find the DVD.
After that the Windows 8 install will automatically start, just follow the instructions on screen.
After install, power down the system, reconnect the HDD, boot again into Windoze. Format the HDD with Windoze. If you install Windoze apps, change the install destination folder each time to D: instead of C:. When you create content, make sure it goes to D: everytime, this is done by changing your libraries from the default folders in C: to folders on D:, and changing the settings in many applications that have the ability to set the data destination folder. Many applications will still not ask you where to install and install on your SSD and many applications will still write their data to you SSD without the possibility to change that through the program itself. It can however be changed on a per-program basis, mostly by hacking the registry.
Whatever you do, the first thing is to uninstall internet explorer and microsoft security essentials, and download zonealarm and activate it, download malwarebytes and run it immediately, download the free online scanner from ESET, download CCleaner to keep your Windoze system healthy, download "Start Is Back" to fix the Windoze 8 interface so that it's usable again, etc...
Warning: setting up Windoze takes time, several hours to install it completely!
Recommended optional upgrade: Download Fedora 18 64-bit Gnome from fedoraproject.org, burn it on a DVD, reboot with that DVD so that Fedora starts as Live OS. Click the "Install to Harddisk" icon to install Fedora 18 next to Windows 8 with the easy to use installer, and set the "/" (root) and "/swap" volumes to the SSD and the "/home" volume to the HDD, so you don't have to worry ever again about what goes where or about malware. When it's installed, click yes to the updates that pop up and google "Fedora Utils" and install it as mentioned on the site to install everything you need, including SKype, Steam, Microshaft fonts, Whatever, in a few minutes. Warning: setting up Fedora is fast, until full install it takes less than 15 minutes.