The Client Software, is called FileMaker Pro unless you are using a web browser, an iPad or iPhone to connect to the database. There is no "connecting" to do. You just need an installer for FileMaker Pro to install it on the client machine. If using an iOS device, you just need to go to the app store and get the free FileMaker Go app unless there are FileMaker Pro files created by that teacher to install on that iPhone or iPad as part of the solution.
So best guess is that you just need to find the installer and license keys for FileMaker Pro and install the software. If necessary, you can contact FileMaker Tech Support and request a new download of the needed installer(s) provided that you can provide them with proof of purchase.
Thank you for the information. I finally found the FileMaker Pro software on a flash drive on his desk. Installed and connected. Life is better now.
Again, thank you for the direction.