Using a program with 2 or more computers

I have an office software program I designed that handles appointments, ledgers, etc. at a front desk computer and allows me to write notes on my laptop and then later transfer these notes via a floppy disk to the desktop unit. I am considering some options for change but no next to nothing about networks. I may try to set up three desktop computers (one in each room) and connect them to the front desk system.

1) I do not know what cables, etc. would be needed for this, additional hardware, etc.

2) I do not know the ports that would be best to use, USB connection, parallel port connection, modem connection, etc.

Once the network was established, the simplest of my ideas would be to  have the 3-computers that only take notes communicate to the front desk system by assigning the network drive for that note file to the front desk unit. Am I right?

I also had an idea for a future system, where all rooms could access the information stored on the front desk system but I am unclear as to the best way to accomplish this. I see these possibilities but I have no idea which one if any would be the most practical.

A) All 4 computers have the same software installed but all data is routed to the front desk system.

B) Only the front desk computer contains the software and data but the three other computers can access the front desk computer.

C) There is only one computer, the front desk computer, but the 3 rooms have “dummy” terminals (keyboards and monitors without a computer) to connect to and access the software.

My concerns are:

For setup A...None, this system should only require the appropriate file handling routines to lock and unlock files, which I am already aware of.

For setup B...Better than A in that only one computer needs to have the software loaded to it. Is such a setup possible? If so, my concern would be that a shell could be opened from each room computer so different users could do different tasks.

For setup C...Better than B in that only one computer is needed. I would imagine that this type of setup would require extra hardware such as a router to communicate with the front desk system. I am completely uncertain about this type of setup but I would imagine the same “shell” program would have to run in from the front desk system so each terminal could be used as a separate independent work station.

Anybody still with me so far? This if probably simple for those in the business of setting up networks but I have to date no experience with such accomplishments.

Hoping for some good insight here,

Pete