You should probably specify wether you're talking about Metaquotes' own VPS service or any other VPS service (e.g. offered by your broker).
With a normal VPS service you usually just log in via a remote desktop connection to a Windows Server 2012 installation and use it pretty much
like any normal home PC, meaning that you can install as many terminals as you want. Regarding Metaquotes' proprietary VPS somebody else
needs to answer the question, cause I don't use it.
With MQL5 VPS is one trading account per server.