NOTE: This will NOT work well with URL rule conditions. For example adding in URL contains 'cart'AND 'user intends to leave with back button' will NOT work. Why? Because the technology works when a user is using the back button to leave your website, not using the back button anywhere.
The primary rule in this setup tracks the mobile Back Button when a user clicks the back button within your site and they are about to leave to another site. This means that if a user is browsing your site, no matter how many pages they've viewed during that session, the overlay will trigger only when they attempt to leave using the back button on the landing page, which is the page that the visitor entered your site with, not from ANY page they are on.
1. Create a mobile promotion; check out this article to help you with the initial set up.
2. In the rules section, also denoted STEP 2 of the promotion design process, click "Add New Rule". Then name the rule and select Advanced Rule before clicking "Create Rule" to continue onto setting the rule conditions.
3. Add in the "Exit with Back Button" rule and any other conditions you may want for the mobile exit offer, but always keeping in mind the limitations of URL conditions with this type of exit rule.