Filemaker server is not a substitue for Filemaker Pro, they are not the same.
You will need FMP to design your databases.
You will need FMServer to HOST those databases for a multi-user environment.
FMP itself can act as a small server for your solution, but is limited as to how many clients can connect to it (i think 5 or less)
You do not need to have FMP on the same machine as the FMServer SW, you can make all your edits to a hosted file over the network.
Thank you very much! Exactly what I needed to know.