Welcome to the forum. BIAB supports time signatures of 4/4, 3/4, and 2/4. Working with songs of other time signature requires a workaround in the form of how you think about other meters. You should be able to make it sound right but not necessarily look right in notation.

First question: did you select a style that is 6/8?


BIAB 2026 Win Audiophile. Software: Fender Studio One 8, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Presonus Quantom HD8 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.