A2: You probably forgot to press the PAUSE button first.

You start EDITING as per 6.4 on page GB34.
Item 6.4.4 says 'Press the OK key. If you do you get a window saying DELETE EDIT or CANCEL which leads up a blind alley as far as editing the recording is concerned.

What you should do as per top of page GB37 is press the OPT+ key which brings up the Function Bar and things start to make sense. Here the recording is already being played (Contrary to page GB37 of the manual which says press PLAY as the next step). But the buttons on the left of the function bar don't work. It is at that point that you have to press PAUSE to get them to work.