When it comes to applying a style in Excel, there are a few things you need to keep in mind. First and foremost, you need to make sure that the style you're trying to apply is actually compatible with the version of Excel you're using. If you're using an older version of Excel, then you might not be able to use some of the newer styles that are available. Secondly, you need to decide what kind of style you want to apply. Do you want a cell style, a conditional formatting rule, or something else entirely?
Once you've decided on the kind of style you want to apply, the next step is to actually select the cells that you want to apply the style to. You can do this by clicking on the cell or range of cells that you want to style, or by using the keyboard shortcut Ctrl+A (Windows) or Cmd+A (Mac) to select all cells in the worksheet. Once you've selected the cells you want to style, it's time to actually apply the style.
If you're applying a cell style, simply click on the desired style in the Styles gallery (located in the Home tab). If you want to be more specific about which cells get which styles, you can use conditional formatting. To do this, select the cells you want to format, then click on Conditional Formatting in the Home tab. From there, choose from a variety of options to format your cells.