There are 5 keys with labels [ A ], [ B ], [ C ], [ D ] and [ E ]. Clicking one of these while in prog mode will put the key label in the program. Clicking one while not in program mode will start the program at the key label if it exists in the program.
The label after a [GTo] does not have a number sign before it, but the locating label does (e.g. #A). Labels are searched for from the beginning of the program list. Only the first label will be found if there are two or more of the same label.
You may step through a program one step at a time with the key labeled [SSt]. The program line will be displayed in the big register under the calculator and the step will be performed. The prog mode must be off to do this. A small field at the left with "Running" in it will be displayed while the command is executed.