I don’t use the Salzedo font, myself, but I believe you would attach the bracket as an
articulation or measure expression. It’s basically a text letter (the bracket key, I think) in
the Salzedo font and you would resize it by changing the font size.
I myself prefer to draw brackets with the line tool. If you do a lot of brackets (I don’t
include fingering so I don’t need them a lot), your best bet is to use the shape designer to
create a vector shape that can be pulled in different directions to alter the angle of the
bracket. (You’ll need to duplicate it each time to avoid changing the angle on all your
brackets, I think.)
If you don’t know how to use the shape designer, ask in the Finale forum. They are very
helpful, for the most part. (I haven’t had occasion to use it in the past few versions and
things are pretty different now, so I don’t feel confident telling you how to do it.)