First you need to download all required files:

1. Download Server Files
2. Download Server Launcher
3. Register your server here
4. Run ZServer.exe
5.1. In ZServer add server exe and set params to this for BFBC2:
-zlogin ChangeMe -zpass ChangeMe -port 19565 -mapPack2Enabled 1 -serverInstancePath "ZEXEPATHZ/InstanceBC2/" -timeStampLogNames 1 -region OC -heartBeatInterval 300000
zlogin and zpass - from step 3.
5.2. In ZServer add server exe and set params to this for Vietnam DLC:
-zlogin ChangeMe -zpass ChangeMe -port 19566 -mapPack2Enabled 1 -serverInstancePath "ZEXEPATHZ/InstanceDLC/" -timeStampLogNames 1 -region OC -heartBeatInterval 300000
zlogin and zpass - from step 3.

In InstanceBC2 or InstanceDLC edit ServerOptions.ini and replace all ChangeMe to something useful.

Use Procon Frostbite to configure your server.