ener.hlp (Topic list)
Restart (Alt+R,R)
■ Clears memory and highlights the first executable
  statement. Use as an alternative to Start and Continue.
 
■ Use F8 to step through code one statement at a time, or
  F10 to step through code one procedure at a time.
 
■ You can alter which statement will execute next with the
  Set Next Statement command from the Debug menu.