Push New Campaign button and then create Activity Popup campaign.
Create memorable campaign name that you can distinguish later
Now you see random Activity Popup set by default. So let's get started:
Set the Goal - you can go without it to be honest. It depends of your desire to make it more results-oriented from collecting emails to just viewing of content. In order to learn more about how to set goals for your campaigns, I would like to recommend you to read a separate guide on how to set goals and why do you need that;
Design your campaign add text message, change colours, patterns. Edit your text message, place it on the bottom/top/right/left, turn black theme on. Simply make it look fancy;
In Behaviour section you may set where and when Activity Popup should appear
Schedule campaign in Settings section;
Choose type of device on which you're planning to run your campaigns, put your page's URL and include or exclude locations to show the campaign