Hi and welcome to one of the most friendly and knowledgeable sites on the web.

I would suggest that instead of importing MIDI files I would put the chords in BiaB and experiment with the various styles, both MIDI and RealTrack/Realdrums. Once you are comfortable with that then play around with some of the other features like melodist, soloist etc.

After you have this down you can import your song into your DAW, in your case probably RealBand. There you can separately record your Uke on one track then your vocal on another, mix and master your song.

I know this sounds like a lot but just take it slow, have fun and feel free watch the tutorials and ask questions.

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