Go to Appearance > Widgets to add your advertisement code in a text widget using the sidebar called "Single Right Advertisement". Shortcodes are allowed in this section.
I dont think Ive read anything like this before. So nice to find somebody with some original thoughts on this subject. realy thank you for starting this up. this website is something that is needed on the web, someone with a little oryatngliii. useful job for bringing something new to the internet!