IBM PCjr Manual page 56

Now that we've come to the end of this adventure,
we're sure you'd like to know how it ends and how you
can begin it again later.
If you wanted to go back from this point and start over,
you would hold down one of the Shift keys and then
press the Fn key and the F9 key. (Then you would
begin again at Step 4 of the "Keyboard Adventure.")
Shift
If you wanted to repeat only the keyboard part of this
program, you would hold down one of the Shift keys
and then press the Fn key and the FIO key. (Then you
would begin again at Step 10 of the "Keyboard
Adventure.")
2-40 Getting Started