Hi @MarisaKordecki ,
Screen group templates have other preset settings, such as the transition effect, spacing between panels, and when to trigger the next screen. Therefore, when you select a screen group template, any new screens added to the screen group will have the same amount of space.
The screen group template used in Parallax is Showcase, which you can find at https://doc.arcgis.com/en/experience-builder/latest/build-apps/add-screen-groups.htm#ESRI_SECTION1_ ... to refer to the template setup.
Screen groups are used to provide a different scrolling experience for the end user, if you are concerned about spacing you can remove the screen group and add four blocks to replace the screens. You can add a column widget to the block to achieve a similar layout.
Regards,
Shengdi