這是seller 發給你的？我的理解

each category associate with a brower note, for example, Books ( brower note is "ABC" or "123"), Textbooks ( brower note is "ECF" or "489"), Humanities ( brower note is "KO" or "982"), etc.... something like that.

if you couldn't find your book by searching "Books > Textbooks > Humanities > Foreign Languages > Chinese", that means brower note could be wrong for your book.

I have no idea what“BTG file”is, if you have it, please find correct brower note in it, and send them back. they will update for you.