
On clicking the add-ins menu item Excel will generate a user dialog of the add-in software cuurently known about and available to use. The checked items are already activated.

Use the browse button to search the file system for 'ACBA-Tools.xla'. The default location for Add-Ins is generally
Some older systems may refer you to the Program Files directory. However, if you have just downloaded the ACBA-Tools.zip file you will find the add-in in the ACBA-Tools directory of the unzipped folder.
Having located your software select it and click 'OK'.

With some operating systems you may be asked whether you want to copy the add-in into the default location. You should answer No.