T2T,
All you need is to create an Information Bay from server-manager, a 'folder' is automagically created for you.
You need to set correct permission to access it from other platform.
I-bays is a unique feature of SME Server. It is powerful, simple, and flexible mechanism for creating distinct information-sharing sites.
However, SME is overkill if you want to use it only for fileserver/ftp server.
SME server is a fileserver, mailserver, mysql server, webserver, proxy server, firewall with a very secure configuration out of the box. Basically all you need to set up a small/medium enterprise server provided in SME server.
All provided with very simple interface to setup and maintain, and included a simple automatic software updating mechanism.
SME server can be enhanced with software packages (in SME we call it 'Contribs').
Contribs created for sme including VmWare Server, VOIP PABX Server server, Backup Server, and some Web Applications.
I suggest you to use FreeNAS as it is more lightweight for Vmware.