Yoy may enter labels in the program to control branching. Click in the [Lbl] key while in prog mode to enter a label into the program. Enter the label (single character) in the dialog box. Click on the [GTo] key (while in prog mode) to have the program branch to the specified label at that point. When the program mode is off, clicking [GTo] will put the step pointer at the label entered in the dialog box if it exists. The default for [GTo] is "start", which is the beginning of the program. Any other label must be a single character.
The [GSb] key branches the program to a subroutine. The label of the subroutine is asked for in a dialog box. The subroutine must be ended by clicking the [Rtn] key. Only one level of subroutine is allowed.