Your computers will be networked as long as they are all connected to the same router or switch as long as they are configured correctly. (Same workgroup name, etc.)
As to your AC question, when you install AC to the main computer, you will install SQL and the program. On the other machines, you will choose not to install SQL. They will then be able to browse to the database on the "main computer." With your setup, you could probably get away with using your computer as the main computer.
