Zend certified PHP/Magento developer

Change background color of magento theme

I’m arranging the product sheets of an ecommerce made with OpenMage and JAKESHARP WATERLEE theme.
I need to change the background color of the theme, but if I go to JAKESHARP WATERLEE -> Theme setting I find only a dropdown menu with the words Waterlee settings -> enable ->yes and nothing else. There is no control panel where I can take action.
Maybe it depends on the fact that I was not given the necessary permissions, but I would like to understand if to change the color I should go in this section or act somewhere else.
Sorry for the obvious question but I’ve been working with WordPress for years and it’s the first time I’m dealing with Magento.