If the song is all Realtracks (RTs) look for a line under each instrument, i.e. drums, piano, etc. If there is a line under all instruments then you can save it as MIDI. However if there is no line under the instruments then you can not save it as MIDI.

Let us know what style you are using so we can check it out.

If you can drag and drop MIDI files into Cubase then using the DAW mode is the easiest way to proceed IMHO. I can drag and drop a complete MIDI song from BiaB to Studio One Pro 6.

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware