Email providers don’t generally allow scripts of any sort to run in emails for security reasons.
Because of this, placing ads in emails is really just adding an image and a link. If you’d like to track the link for statistics, you can use Google UTM codes or follow the instructions found here to track via AdRotate.
Outside of statistics, you’ll just need to add your media image file to the newsletter template and add a link to it to whatever URL the advertiser wants you to direct it to.