The Challenge of a Challenge

I have a couple of idea for reading challenges that I want to host. I'm still pondering the details, but my ideas involve using my Must Read lists, maybe in some comparative manner. I wouldn't duplicate existing challenges. But there are so many questions I have! I am challenge challenged. Please help! I would greatly appreciate any information you can share or resources you can direct me to regarding at least the following: 1) Is it acceptable or advisable to start a challenge mid-year? Most challenges start in January -- will it work to launch a new challenge in May? Would it be better to limit the number of books? Like maybe five or even three? Or do I have to wait until next year? 2) How do I make a button for my challenge? Everyone has such cute buttons and I am stumped. I'm talking basics -- like how to add text to a picture. I could do it as a Word document (Word is my only computer "tool" so I can do just about anything with it), but I don't think that will work as a blog button. Are there any on-line instructions available? 3) Assuming I can figure out how to make the button, how do I make the button into a link? I don't want someone to click on the button and have it simply open as a picture. I like the kind of buttons that people participating in the challenge can add to their own blogs. 4) The big question: What if I host a challenge and nobody comes? To avoid ignominy, could I then sign up imaginary participants? What about my cat and immediate family members? 5) With that in mind, what are the best ways to let people know about my challenge? Like I said, I'd appreciate any guidance. I don't want to be a challenge dunce!