Preparation!?

[Shex]

So I decided to try again to make a petsite with use of the Mysidia script, because I can't code anything myself. But I don't want to just take the script as it is and maybe just tweak the css, I want to make real changes in design and function, so I really want to know:
How can I prepare myself?
Especially: Which programming languages should I learn or take a look at?
What about MYSQL and php frameworks? Anything else that can help me understand the script and code myself?

What I already did is installing WAMP with the guide by Kyttias and install the script, also I started brushing up my html and css on codecademy

Thanks a lot in advance :)