Heelium comes with an easy-to-use administration panel. You can access it by navigating to the Dashboard > Appearance > Theme Options. The theme options are conveniently spread over a number of sections, and each section contains the options that pertain to a particular area of the theme. The options allow you to set general styling and layout, as well as styling for each section of your website (posts, pages, widgets, header and more).
Find more information about the different sections: