Select the Performer Layer to edit the placement over performers throughout a chart. 

Tap the Performer icon in the editor menu which will slide the 'Green Room' into view. To add a performer to the stage, tap the performer you want on the stage and the icon will appear center stage and a 'shadow' of the performer will appear in the Green Room. Then, drag the actor into their position on stage. You will notice that the floating actor placement number  floats above the icon and automatically adjusts according to the position (stage right or stage left). The number will only show if the actor placement option is turned on in the Chart Settings tab of the Production Menu