Debugging current website

I have a current website that needs debugging. Subscribe button doesnt work. Custom form on my site needs adjustment (alignment, new submit button, and being able to submit regardless if the some of the fields is missing) Once people subscribe I would like the contacts to be stored correctly on the back end of Joomla. I would like the subscriber to get confirmation as well in a pop up.."Thank you for subscribing" On my custom form I would like clients to get a copy of the email as well once they submit their information. Also I would like the same text/font/size consistent all through the entire website.