Checkdomain explains here how to build a popup for your website and how to display it only at certain times. 

To create a popup, click on Pages in the left menu bar and then on the Popups tab. Now click on the blue button "New Popup". In a new window some types of popups will be suggested to you.

In our example we select an empty popup and assign a title, e.g. voucher action. Now click on Add to create the popup. Select the Popup Settings button at the bottom of the preview.

There you can now set the height, width or background color of the popup.

You can also simply click on elements in the popup and change the font color or the text, for example. Click on the button to save the text and the respective link.

Back in the popup settings you can set different popup animations and, if desired, one of the colors for a page overlay. After you have designed your popup, it is advisable to view it again on all three screen sizes.

If you switch back to the starting point, all created popups will be listed here. Click on the gear to rename, duplicate or delete your pop-ups.

In order for your popup to be displayed later, you still have to activate it. To do this, switch to the Personalize menu item. Here you have a number of rules at your disposal, we first create a user-defined one. For a rule you have to define a trigger, usually you use a time-controlled trigger for this. In our example, we want the popup to always be displayed and set the check mark for no trigger. Then click Next. Now the action is added, so what should happen when the page is called. Click Next. Now select the page on which it should be displayed, which popup and when it should appear. By clicking on Next you will be shown a preview. If everything is to your satisfaction, click on Done in the upper right corner to get to the Final Settings.

There you can name the rule and determine whether this rule is only applied once per visitor. Then you can save the rule and check the box Publish now - and the popup will appear.

However, you can also link popups via an image, for example. To do this, click on the desired picture in the menu of a slide show and switch to the picture settings. You can now select your popup under the item Add link to image. No matter what you set, your popup will appear in preview mode.