Can't Click "Please click here to confirm this appointment"

http://www.niagarafleamarket.ca/make-an-appointment/

What the heck have I done? Do I need to have marketplace installed as well? I can't submit to test and see if this is working... so it clearly isn't...

Are there more backend things to setup on Paypal? I've never used it to collect payments before. I haven't set up Google.. I only added the button.. Do I need to do API key? Sorry, I've read through a ton and watched videos but it just isn't getting any clearer for me!