How do I indent text in a cell (using Numbers)?

I'm using version version 4.3.1 (5249) of Numbers. How do I reliably & consistently indent text in a cell?

The HELP feature on Numbers directs me to:

1) click on FORMAT

2) click on TEXT

3) click on "Increase [or Decrease] Indent Level

HOWEVER no matter whether I just click in the cell -- or highlight the text within the cell, the "Increase Indent Level" AND "Decrease indent Level" options are greyed out and do not work.

Please help! Thank you!