Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
First, let me give a bit of advice and detail about SSD's. SSD's allow data to be accessed faster then a normal Hard drive.
If you want to see the best results, my suggestion is to install programs on the SSD.. and also your main operating system. That way the mac, and any programs it runs will open and run a little faster. Use your normal HDD to store videos, documents, data, etc.
As far as why the Photoshop program wouldnt work when you put it on the SSD. Did you do a fresh install of photoshop to the SSD? Using a download or a cd? Or did you just copy the files over?
As far as how to see the space your hard drive is using up. There are paid programs that can give you more information, and allow you to easily delete and remove files or clear space. But the simplest way to see a general view of whats on the hard drive is built into the mac already.
Heres how to view it.
Im sure you may have a few more question and need further assistance. Please dont hesitate to respond when youve had a chance to read over and try out what I suggested.
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