Created attachment 130210 [details]
screenshot about adding rules

Refer to the attached new screenshot "Calc-autoformat test.jpg" (added more notes to better clarify the rules) and to bug 95182 about help documentation discrepancies.
The new "Calc-autoformat odstest.ods" can be used to create and save the two autoformat models "testX" and "testY" I used for testing.
The new "Calc-autoformat odssample.ods" is the sheet used to test and verify those rules. From here you can copy cells A1:G11 to a new sheet and repeat the test yourself.


a) Rules for ADD the current formatting to the list of predefined AutoFormats:
1- Select all the range of the formatted "model" sheet (at least 4 x 4 cells) and click on Format - AutoFormat.  (NOTE: the local and online helps say "Select all" but it is wrong, you have to select only the formatted cell range (at least 4 x 4 cells) you wish use as a model).
The AutoFormat dialog then appears.
Click Add, then enter a name and click OK.
2- Then, in the formatting options (usually selected), deselect those currently in your spreadsheet you want to keep into the predefined AutoFormat.
In the preview field you can see a preview of the predefined formatting.
Calc AutoFormat stores a predefined format using these criteria: the first row and the first column selected are considered to be “titles”, the last row and the last column are considered to be “totals” and other cells are considered to be "data".
3- Click on OK or CLOSE.

b) Rules for APPLY a predefined AutoFormat to a sheet:
1- Select the range of cells (at least 3x3) in the sheet to be formatted. 
2- Open the the AutoFormat dialog clicking on Format - AutoFormat.
3- Select a specific formatting from the list of all predefined automatic formatting, select/deselect those options you want to be discarded/applied into the marked sheet.
4- Click OK to assign the format to the marked sheet.
The predefined AutoFormat will be applied to the new sheet regardless of the amount of cells to format (that is "titles/totals" formats will be applied to the first row and the first column in the selection, "data" formats will be applied to all other cells in the selection).

c) Rules for DELETE/RENAME a predefined AutoFormat:
1- Open the the AutoFormat dialog clicking on Format - AutoFormat.  Note that the AutoFormat selection is usually inhibited; in order to disinhibit it, previously select fictitiously a range of any cells (but at least 3x3).
2- Select a specific formatting from the list of all predefined automatic formatting.
3- Click Delete or Rename.  Cicking Rename you will be asked for a new name, enter it in and click OK.
4- Click on OK or CLOSE.