Make SSD in Mac Mini 2011 Boot Drive Only - El Capitan

I have a Mac Mini Mid 2011 version. I'm upgrading the original hard drive to add an SSD to work as a primary boot drive. I basically want the SSD to work as the boot drive, to run Photoshop and Lightroom (I'm a photographer) and run all of the apps. But all of my writing and storage is to be on the other hard drive. How do I set this up? I've seen how to install and clone the hard drive, but I want to set it up like this.

Thanks