It is not uncommon to work on projects that require several workbooks. When you are naming files for your project, you should use names which will later sort properly when you use various functions of Excel. For instance, the Open dialog box shows the files in the current directory. If your files are named properly, they will always appear in order on the list.
I ensure this by starting all files related to a project with a number of digits that represent the order in which the workbook appears in the project. For instance, if the project entails workbooks from the last quarter of 2012 and the first quarter of 2013, then the files may be named as follows:
201210 Actual Figures.xlsx 201211 Actual Figures.xlsx 201212 Actual Figures.xlsx 201301 Actual Figures.xlsx 201302 Actual Figures.xlsx 201303 Actual Figures.xlsx
The files sort properly because they beginning with the year. If they began with the month, then the first quarter of 2013 would sort before the last quarter of 2012, which is not nearly as helpful an order.