If you want to add some customizations to your code, you will need to add some code for example in style.css file (CSS), custom.js (JavaScript) or functions.php(PHP). Please be aware that we do not support your customizations, so be sure that you know what are you doing.
Also, we don’t support some third party plugins because we do not know how that plugins can react on plugins that you get with our theme. In that case you can get some serious issue, so keep an eye on it.