1, first enter "= vlookup"
2, that is, according to the book number, find the book title and enter the book number of the grid, comma.
Look for what you need in that area. The corresponding relationship between "book title" and "book number" is in the book number comparison worksheet. So go and number the chart area of the worksheet.
The name of the book is in the second column of this area, so you should fill in a comma 2, then match it exactly and press Enter.