The [Pgm] key toggles the program entry mode on and off. When it is on, a field at the left displays "Program". Every programmable key that you click in is recorded in the program memory. When the program mode is off, clicking the [R/S] key will run the program starting at the current program step. When the program mode is on, the [R/S] key will be recorded in the program. This will will stop program execution while running a program. You then have access to the keyboard and all functions. Clicking [R/S] will restart the program at the next program step. When the program is running, "Running" will be displayed in place of the working registers.
When entering a program, the function keys still function normally. Thus if an illegal value is in the x register for a particular function, you will get a beep, and the function will probably not be entered into the program. Be sure to have legal values in the x register (and memory if you will be recalling it) before starting to enter the program.