I'll try to explain further, but it would help if you could describe what you do, and do not, understand so I can be of more help.
Here's a graphic of a Keynote Slide with two boxes; the blue one is a Table Cell and the red one is a Text Box.
It isn't necessary (if you're not going to save the Table), but I reduced the Table to one cell by deleting all but one row and all but one column. The text box just happens to be one of the default boxes in the template, but could also be one that you add.
Double-click in the Table Cell to get the formula dialog that you see in the Table cell and enter the formula shown. Hit Return. Format the cell to display the date and time as you like.
This date and time will update every time you open the document, and possibly at other times as well.
This next graphic shows the date and time as they appear in the Text Box:
To move the Date and Time to the text box, click once on the Table Cell to select it (the sizing handles will appear). Click again right over the Date and your cursor will change to a hand.
Now 'Click and Drag' the Date to the Text Box. The Date and Time in the Text Box is now frozen and will not be updated.
That's my answer to your question. Not as convenient as you might like and maybe not as easy as just typing your entry directly, but it works.
Note that it was 7:55 when I created the =NOW() function, 7:56 when I copied the Date and Time to the Text Box, and 7:57 when I made the second screen shot.
Hope this helps.
Jerry
