First Triathlon in September....have a few questions

Hi there....I will be competing in my first triathlon this September (The Great Atlantic Ocean Tri, Seaside Heights, NJ) and I had a couple of questions...

First, I recently purchased a bike and don't really know anything about cycling.  Actually, I don't know a single thing about cycling as this is my first bike since I was about 12 years old. 

First question is my bike didn't come with pedals....what to do about this?  I was able to get a pair of cycling shoes from a friend (Shimano TR-02) but I'm not sure what pedals to get for these shoes?   Are pedals specific to shes and vice versa?

 Also, I am pretty sure just from looking at pictures of shoes that there is supposed to be something else on the bottom of these shoes...seems like something screws into them.  Can I just go to a local bike shop and get this figured out?

I realize these are pretty elementary questions but for my first tri, I figured I would start training, get the equipment as I went a long and sot of figure it out from there.

Any other advice anyone has re: cycling or tris in general would be greatly appreciated?  Also, is there any other equipment that people think is absolutely necessary, aside from the obvious (suit, bike, helment, shoes...etc.)?

Thanks for reading!