The styles option allows you to design and save for future use formats and combinations of formats that you may want to apply to certain cells in your spreadsheets. Styles can save you a lot of time, especially when the combinations of formats are complicated.
Design a new style as follows:
Open up the "Format" dialog box by either selecting Cells from the Format menu or right-clicking and selecting Format Cells from the drop-down menu.
In the box, click on the Styles button at the bottom left corner to open up the Styles Design box.
You can now use any, some or all of the six format options (accessible through the six tabs along the top of the box) to help design the new style. Set the required formats and then click in the top line of the Styles Design box.
Type the name of the style. This will activate the Add button, which you should now click on to place the new style in the box below, in which styles are listed and saved for future use. (Note that the add button will only be activated if the new style has a different name from those already listed.)
Once this is done you can do one of three things: continue to design new styles, as described above, and add them to the list; exit the dialog box altogether without applying a style; or apply a style there and then.
Apply a style by selecting it from the list and clicking on Apply. When you click on OK the style will be applied to the currently selected cell or range of cells. (If you choose not to apply a style, clicking on OK will close the box without affecting the spreadsheet.)
You can go back to the "Format" dialog box at any time to design new styles or apply old ones. Also, you can delete a style by selecting it and clicking on the Remove button.