The Step commands allow you to move through a program by executing one or more expressions at a time.
To step through a program from a breakpoint
 Click the Step Into button, or choose
                  Debug 
 Step Into from the VLISP menu. You can also press
                  F8 to issue the Step Into command.
                  Execution begins and halts before evaluation of the inner parenthetical expression, that is, before the specified division occurs. The expression is highlighted, as shown in the following figure:

 
 Now look at the Step Indicator button
                     on the Debug toolbar; it is the last button on that toolbar.
                  
The Step Indicator button is active when you are stepping through a program. It indicates where you are in relation to the expression at the breakpoint. The current symbol indicates that you are stopped just before an open parenthesis.
 Click
                  the Step Into button again. The cursor moves to a position directly after
                  the evaluated expression, and the Step Indicator button indicates this.
               
 Now
                  take a bigger step. Click the Step Over button, or choose Debug 
 Step
                  Over from the menu, or press SHIFT + F8 to issue this command:
               
With the Step Over command, VLISP evaluates an entire expression (and all nested expressions), then stops at the end of the overall expression. The cursor moves to the end of the evaluated expression.