To insert advertisements in the header and footer go to the Theme Options page of your theme and locate the header and footer content options (not available on all themes).
To insert advertisements in your sidebar go to Appearance > Widgets and add your ad or image code into the Text Widget.
To insert advertisements within the page content go to Appearance > Sidebars Editor and insert your ad or image code into the Raw JS Visual Composer element (not available on all themes).
You can also use a variety of ad plugins to insert advertisements within your posts/page. The plugin "Wp-Insert" has been tested with this theme.