You can easily filter the profiles that have filled out a pop-up (to subscribe to the newsletter, for example). This allows you to target these profiles immediately after they fill out the form.

Create a new trigger. Open the filtering system by clicking + add new filter.

Go to the Profiles heading and look for the line Completed one of the following popups forms (or search for "pop-up" in the search bar). Click on the rule. In the rule, then select the corresponding pop-up and enter the desired time.

Now complete the corresponding email and activate the trigger.