When you extend a cycle, all the sheets after the white dash are repeated sheets. The repeated sheets are linked sheets, and any modification on them will be applied to their sisters.
When you are on a linked sheet, the information “Linked sheet” is displayed in the bottom bar and other linked sheets are highlighted in purple, telling you that any change will affect the other linked sheet(s).
The linked sheets can display corresponding numbers to help you visualise pairs in a quick glance. The numbers correspond to their order of creation.
You can remove the display of these numbers in the Timeline settings, switch off Show symbols for linked sheets.
When a cycle is selected, you can choose the cycle type by tapping on the cycle icon in the action panel.
If you want to break a cycle, or to edit the sheets in a cycle, these options are available in the action panel: