I don't know what version of BIAB you have, but in the 2023 version, it's very easy to add bar lyrics from a text file.
Simply create a text file using (say) Windows Notepad or BIAB's "Big Lyric Window" (found under the "Window" menu) and arrange it so that each line of text contains the lyrics for one bar of the music.
Now...
1) copy the text to Window's clipboard
2) open the "Bar Lyrics" layer on the chordsheet (see image below)
NOTE: if your view of BIAB is different from that shown on the image, press CTRL+T to change views.
3) position the cursor in the bar lyrics at the bar where you want the lyrics to begin
4) select CTRL+V to paste the lyrics
In the manual, there is a section with the heading "Adding Bar-Based Lyrics" that explains this. I suggest opening your manual and searching for that phrase.
Hope this helps,
Noel