I still struggle to map out Banjeaurine parts properly. Especially when transposing them from A notation. I had set this one aside some time ago when I simply could not get the two parts to sing in the same key. Turns out it was my software ("If I only had a brain...").
A jog in the right direction from the kind forum denizens of Musescore and, well, here it is!
This is taken from "The Crown Method", a tutor by Thomas Armstrong that is available in the Internet Archive...probably should be downloaded to here in the Tutor Books section too.
The Crown Method