Single step or F5 is an option that can be used to go through a program by every statement, in the function modules and subroutines that will run also step by step. After the processing of every function module or subroutine with the aid of the statements CALL FUNCTION and PERFORM the control can go back at the statement. Execute or F6 is an option for running a program with every line, so in a single line the statements will be processed all at once. When we use Execute and we are on a line invoking a subroutine , the entire subroutine will be processed and it will go to the line with the subroutine invoking, and we can go from statement to statement inside the subroutine. Return or F7: When control is going back to the main program, also the debugger will go back there from the subroutine. Return is an option that is good for going back to the invoking program from a subroutine , invoked program or function module. Continue or F8 is an option good for processing the program up to the following dynamic or static breakpoint or the location of the cursor. When the breakpoints don’t exist anymore and there is no cursor, the remaining part of the program will be processed normally and the system will go out of the debugging mode.