A pro forma usually needs more than one sheet: a schedule, a cashflow, a set of assumptions kept apart from the calculations that read them. Spreadsheet's sheet tabs work the way Excel's do.
Add a sheet
Click the + at the end of the tab strip to add a new, blank sheet.
Rename a sheet
Double-click a tab to rename it. Press Enter to commit the new name, or Escape to cancel.
Reorder sheets
Drag a tab along the strip to move it. A caret shows where it will land. The Usages sheet can be reordered the same way as any other tab.
Delete a sheet
Select the sheet, then click the × that appears on its tab, and confirm. Deleting removes the sheet and everything on it.
🚨 Deleting a sheet deletes everything on it. This is not undoable the way clearing a cell is.
A workbook always keeps at least one sheet you can edit, so the last remaining one has no × to delete it with.
The Usages and Features sheets cannot be renamed or deleted
The Usages and Features sheets are system sheets tied to your project's usage/feature table. The tab has no rename or delete control, though you can still drag it to a different position in the strip.
You can edit usage rates and push them back to the project from the Usages sheet.