|"I type the IP address of the server machine into a client browser page "|
Not sure what you mean by this. There are no browsers need in VPN. VPN stands for Virtual Private Network which basically is like have a direct connection to the network. You access the file shares like you would on any network through either UNC or mapped drives.
So to answer your question you would go to My Computer and in the address bar type the UNC path for the other computer like...
or if DNS is getting through the tunnel then you could use the FQDN...
"\\Other Computer\Shared Folder\"
If DNS does not get through the tunnel then you could setup static DNS references in the Host files. You do have to know a little about networking for this project.