The way to do this is by copy/pasting the ad code in "Source" mode, in the CK Editor.
This can be done in all pages where CK Editor is used, even the Right or Left Hand Column if the restricted width permits (Ensure the particular ad is not too wide for the RH column ).
Information on this website is provided in good faith. BusyCMS functions may change from time to time. Specific requirements should be first verified with BusyWeb prior to setup.