No you do not need to get CS6 if you do not want to. Is it suggested? It does have more things that make doing image edting and graphic design easier.
As to where to start, there are many online tutorials out there for you to learn from. Lynda.com has a boat load of photoshop tutorials and you can youtube tutorials as well.
Thank you for the quick reply. No it was not suggested. I was just wondering too if I did up grade how to do that plus. I was trying to take an online graphic design course in 2011 and did not get to complete it so I ended up with this wonderful cs5 and now would just like to know how to use it for basic things like printing more then one photo per sheet of paper and photo editing. Ever video I watch suggest that the veiw (in my opinion) all ready knows how to use cs5 and I do not and I am new to my mac. Anyway I will keep searching the video's.
You can upgrade via adobe's website using the upgrade feature on the photoshop CS6 webpage if you want to do so.
As for tutorials, try Lynda.com some of the videos are free and some are paid for. Deke McClelland is on there and he has Photoshop Basics, Intermediate and Advanced along with his signature series of Deke's Techniques. He's very thorough and explains everything though you will probably need to be a paid member of Lynda.com to get the most out of his tutorials.
Yes a lot of tutorials do assume that most people know what they are doing. I suggest also if you do not wish to pay for tutorials type something like "Photoshop tutorials for dummies". I hope that helps.