green screen learning curve
I do about everything green screen. Make sure the subject is at least 3 ft at a minimum away from the background. I use a free photoshop plugin called easy green screen. It automatically removes ALL green from an image so if the subject is wearing any green it will be removed also. Once it is removed, merge the 3 layers and then you can just move the cutout subject over to whatever background you have pulled up, save as a jpeg and then print. I'd save it first as a psd in case you want to go back to it later. I just use 2 portable flashes to light everything up. If you have one on camera flash do your best to bounce and not get any shadows. Any shadows on the green screen will most likely remain and not be removed causing additional problems.
I also use Green Screen Wizard Pro but that is for when I do portraits, bridals, etc where I have time to work. But for onsite stuff like you have, download and use the easy green screen plugin.