Web Designer for Template Customization - HTML/CSS/JavaScript

I need you to work with pre made website template that I buy from themeforest.net. Those templates have a lot of functionality built-in. All CSS and Javascript is there, but sometimes needs some customization.

Then, I will send you rough ideas/scribbles/Textfiles about the content and functionality I want you to use to build a certain web-presence by using that template.

While this is no heavy coding-work, I need you to be VERY GOOD in HTML/CSS/JS and have a feeling for composition in web design to quickly get the best looking results and make optimal use of the functions the template provides.