The dongles are used to create the wireless network.
Once the wireless network is created then the communication paths are established to permit file sharing and print sharing as desired.
First you setup and configure the wireless network.
You must have all five computers on the wireless network able to see all of the other computers.
Then you simply share a folder on the "one computer" with access rights being granted to the other four computers.
Lots of tutorials avialable regarding File Sharing and how to configure the host system sharing the files and controlling access rights.