The operation steps of "adjusting the font and size of the top letters and side numbers of Excel tables" are as follows:

1. Open the Excel worksheet. The column labels on it and the row labels on the left belong to "Title";

2. In the theme of "Page Layout" option, you can see that the font of the current title is "Equal Angle Light";

3. If you need to modify the title font, click the drop-down option of "Font" in "Theme" and select the font corresponding to the second line of "Title".

4. Click "File" in the upper left corner, and in "General" of "Excel Options", you can find the font size of the current title;

5. Change the font size of "New Workbook" to the required font size;

6. After confirmation, Excel will prompt "Please close and restart Microsoft Excel before font changes can take effect", and click "OK" to close the current workbook;

7. After restarting Excel, I found that the font size of the title has been updated to the set font size.