Via Wifi
Just like MIDI Designer can be connected to an OSX computer, it can also be connected to a Windows computer. The process is almost identical, but Windows does not provide built-in support for network MIDI.

Thanks to the Tobias Erichsen’s freeware drivers, this support can be added. The interface looks exactly like the one on OSX. The tutorial is here and the driver can be found at the top right of this page.

If you’re using MIDI Designer and his freeware drivers to make money as a sound technician, DJ, lighting engineer, puppeteer, etc., please donate to keep rtpMIDI for Windows going.

Via Hardware
Check out this FAQ entry, which goes over your options for MIDI without Wifi. If you don’t use Wifi, you don’t need the RTP drivers.