When you install Windows you'll come to a screen that gives you a choice between "Upgrade" and "Custom (advanced)" install options. If you select the "Custom (advanced)" option then the very next screen will present you with a list of drives to install on.
If the entire SSD shows as "unallocated space", then simply selecting that drive and clicking the "Next" button will cause Windows to partition the entire drive and format it as NTFS before installing.
If the SSD already has partitions and you want to delete them so you can start from scratch, then click the "Drive options (advanced)" link in that window and additional options will appear that let you delete the existing partitions.
The installer and other disk tools in Windows 7...