There are several ways to transpose, depending on the need.

As you say, you could just transpose the whole song up two half-steps and print the part for the sax, then remember to transpose it back. If you did it that way, the sax could not read off the screen and sound correct, any more than they could do so before the transposition.

If the sax is going to play along with the screen, use Opt., Preferences, Notation. Find Transpose options in the middle of the dialog box. Some of the common transposing instruments are available in the pulldown options. The good thing about doing it this way is that the original pitch remains the same; only the notation changes. Again, remember to change it back before you save the song and exit.

I'm not sure if you asked this directly, but the one thing you cannot do in BIAB is have two instruments, one of which is a transposing instrument, read off the same BIAB screen together and have each get the notes they need. That is where transposing in your head comes in, a very necessary skill for the sax player to develop.

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