Here at Excel australia, we use zipped Files
Like many files available on the web, the Rental Workbook file has been zipped to make it a smaller download. You need to unzip the file to a location on your computer BEFORE you use Excel to open the file.
When you unzip the files, choose a folder that you are going to remember – perhaps Documents/Rental Workbook.
Keep ALL of the downloaded files in the same folder.
The Rental Workbook is made up of TWO main files, the Excel one (which you open and use), and a database file which actually stores all of your information – you will not need to open this other file at all.
The other document in the download is the User Guide. Please refer to this for information about how to open and enable the Macros so that you can sucessfully use the Rental Workbook.