After everything is installed to the SSD, make sure it is the first boot device in the BIOS....then you can hook up the HDD and grab w/e files you want off of it.
Then when you're sure there's nothing left on the HDD that you want...just format it...and then use it for storage, or game installs etc.
The free program EaseUS Partition Wizard is a good program for your partitioning needs if you have any.
Proper install order for Windows.
First make sure to disconnect any other SSD's or HDD's, except the one you're installing Windows on, and that it is formatted as Primary, NTFS and Default Cluster Size
Install stuff in this order:
Unhook Internet
Install Windows
Install motherboard drivers
Install vid card drivers
Install sound drivers
Install Security programs
After everything is installed, open Services, and make sure Windows Update is set to Manual.
Rehook Internet
Install Windows updates. ONLY the Important and Critical ones. Read though all those as well, and UN-check any that have to do with vid card, sound or motherboard drivers.
Install utilities like CCleaner, 7Zip, IMGBurn
Install w/e other games or programs you want.
Right after, you do all this and update everything, run all your cleaners and scanners, and tweak Windows w/e, to however you want it...MAKE A BACKUP. Use either Windows built in backup (make the rescue CD too) or free 3rd party Backup software like Macrium Reflect(make the bootable CD too).