To apply a cell style, navigate to the cell you want to format. Alternatively, you can select multiple cells to change them altogether.
Then, proceed as follows:
Applying directly via the dropdown menu of the icon
If you click on the Cell styles 
icon on the ribbon tab Home | group Format, a dropdown menu with various predefined styles (and, if existing, custom styles) opens. Here you can directly select and apply a suitable cell style.
Further down in this dropdown menu, you can use the option Styles in use to display the styles already used in the current document by selecting the checkbox.
For advanced options, click on the entry Manage cell styles in this dropdown menu to open the dialog box (see below and the following pages).
Advanced options: Via the dialog box
| 1. | On the ribbon tab Home | group Format, click on the Cell styles icon and choose Manage cell styles in the dropdown menu. |
| The program displays a dialog box with the list of all cell styles. |
| Tip: You can use the Show option to determine whether all available styles should be displayed in the list – or only those already used in the current document. |
| 3. | Select the desired style in the Styles list. |
| 4. | Click on Apply. |
Immediately, the format of the selected cells will be changed to the format defined in the cell style.
In detail, a cell style can contain the following formatting options:
▪Number format
▪Font (font and font size, text styles, etc.)
▪Cell alignment
▪Shading
▪Borders
▪Cell protection
In the section Format includes of the above dialog box, you can (optionally) specify exactly which of these formatting options should be used when you apply the selected cell style (see also next section).