The sheets tab can be found at the bottom of the sheet.
A sheet can be named to allow for ease of reference. To name a sheet simply double click on the tab where the name is.
Another sheet can be added or deleted. The new sheet can be renamed
Hold the control key whilst pressing on the left mouse key and drag to the position of where you want the copied sheet to be placed.
The position of the sheet can also be moved. By holding down on the left mouse and dragging the sheet to the position you want.