first ... I never used Windows as a openVPN Server
Windows directly to the internet ? ..puhhh
let us talk about tecnical problems.
you will use the standard server setup (there is no really diffence between U*X and Win... may be the path and some small writing problems slash and/or backslash ...)
Your choice is routed or bridged.. -> prefer routed on a tun device.
Each client gets its own certificate, and clients get openVPN-IPs starting x.x.x.6 (each client uses 4 IPs internal) ..you can use 64 clients on a /24 network.
Without CCD [client connect dir] the clients get the next available IP.
You may use a ccd depending on common names of certificates, if each certificate have to get always same IP (depending to used certificate, not to hardware).
may be there are some routes additionally wished, any redirect etc.
What you are using on that servermachine... as you like it, rdp-services btw. too.
FYI: Here we run openVPN-Servers on an IPCop (firewall + router) to call for various terminalservices and more. ( smtp, imap, file services...).
The IPCop ist using an Alix-Board + CF-card (abt. 150 Euros) needs 5..7 Watt and running directly behind Modem.