Wow, those are a wide range of irons and very quite a bit in terms of difficulty.
Go to an outdoor facility and try a few irons. Dont hit indoors as that will do absolutely nothing for you. Go to a range where you can see your TRUE BALL FLIGHT (most important), hit at your own pace, and without a salesman breathing down your neck. Take your time and try to get a good feel for each club. Take a few out at a time and narrow down your choices to 2 or three. Let the club professional see you hit a few and make some recommendations. If you're lucky enough to find the iron that feels/performs the best, set up a club fitting appointment and go for it!!!
I will say that appearance is a very important factor, so be sure you like the aesthetics of the club. If you cant stand the thick topline, super wide sole, etc. dont even bother as you will not have the confidence in hitting that great shot, when you are standing over the ball at address. Golf is mental enough as is...you don't need added stress by choosing a club in which you cant stand the looks.
There's a lot more to choosing the right club fitter, etc., but as for trying different irons, etc. you have to hit them, observe the ball flight and just get a sense for how they feel. A properly fit club can make a huge difference in performance so just ask questions and try, try, try!
Good luck!