There are a number of ways to get a mid file into Studio One:

1:Click on file/save special/ save song as MIDI file

2:Drag MIDI track(s) to the small mid window, click on the small DAW window, open Studio One, drag and drop the track(s) to Studio One by clicking on the small + window and dragging it to the DAW.

3-Click on file/save song. Close BiaB and open Studio One. Load the BiaB VST into Studio One. In the BiaB vst open your song, generate, then drag and drop the tracks to your DAW. Note that you can drag and drop either the MIDI files, Wav files, or both.

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