this is what I did per the instructions that came with my OWC Data Doubler kit
It did take some time to download the os as I am on dsl.
Restart your computer and boot to the internal hard drive like normal.
You will likely get a dialog box stating that a drive is unreadable. Click the Initialize button to open Disk Utility. If you dont get this warning, you can find Disk Utility at Applications/Utilities/Disk Utility.app
Select the SSD from the list on the left side of the Disk Utility window and Click on the Partition tab.
Select 1 partition for the Volume Scheme, set the format to Mac OS Extended (Journaled) and give the drive a name. You can then click the Apply button to format the drive.
Once the drive is formatted and shows in the Finder, you can then shut down.
Make sure youre connected to a network. While its preferable that you connect via Ethernet, you can connect via AirPort; it will just be slower.
Restart to the OS X Recovery Partition by holding down Command-R until you get the Recovery Partitions main window. It is very important to note that you should not use the version of Disk Utility in the Recovery Partition; it will see the two separate drives as a damaged Fusion drive and try to repair it; allowing it to do so will destroy your data.
Select the option to Reinstall OS X choosing the SSD to install the OS on. If youre connecting via AirPort, you may be prompted to connect to your wireless network.
Follow the prompts to install.The actual downloading and installation process may take a while.
After the OS is installed, follow the prompts to set up your computer. When asked, choose the option to import your data from another drive and select your original drive as the source.
Once the migration is complete, your computer should boot to your SSD.
You can use the Disk Utility like you did before and format your original hard drive as desired.
You will now be able to use your Mac mini normally.