I don't want to sound disrespectful, but it seems like you need a consultant to help you. There's a lot to consider with your proposed setup and without some in-depth knowledge of your network and budget, it's impossible to make any recommendations.
A basic setup will be computers > patch panel > switches > firewall > Internet, but like I said, there are other things to consider, such as VLANs, firewall rules, user authentication, server location, etc. which a consultant can advise on.