Hi there and welcome
Apple discontinued this in 2007 ans it does not run nativity within El Capitan. You can get it to work but it will need to be in a virtualized version of Snow Lepoard, so you will need the Snow Leopard Disk to install this in a virtual computer on the Mac and run Apple Works within there.
Or you could convert the documents to a format applications currently can now read and interact with.
If you wish to convert the files, do you have Microsoft Word install on the computer?
ok, Excel should open the Spreadsheet, can you attach one here and I can check for you.