A spacer is an activity responsible for the app layout. You can use it for IOS and Android app design — to add empty space between two activities.
To add this activity and manage app layout types, open the Components section, expand the Layout category, and choose the Spacer.
After you have added the Spacer between two activities, you can set rows and columns number on the right part of the builder (in the Style section). This will influence empty space between two activities.
The Spacer activity itself also has a settings image (a gear). You can add ads there, hide, duplicate, or delete the activity.