A “computer network” is just a multitude of connected computers. This allows the computers in the network to share data and resources with each other. An IT technician can set up your computer network to work on a “peer-to-peer” basis.
This is where computers connect directly to each other. They may also configure the network to go through a central file server. If you hire a quality IT provider, you can consult beforehand to help you decide which option is best for your needs.