Note:
+ Please make sure to not use WYSIWYG editor which might mess up your ads code
+ Assuming you already install MosModule and MosModuleMod and assign MosModuleMod to bottom position would be best in this case
Here are what you have to do:
1. Setup an ads section and category
2. Create one article per ads which you can paste your ads code in them best result not use WYSIWYG
3. Once you have your articles that contain ads in place you can use MosModuleMod to help you to show MosModule in a module and use {mosmodule random=articleID}