Noteman says: See Key signatures, time Signatures, and clefs for a step-by-step tutorial overview on adding clef changes.

Clefs in Finale are intelligent: if you change a clef, the music that follows it is automatically re-notated to reflect the change. Finale can use eighteen different kinds of clefs per piece, but you can re-define any of these symbols or their effects on the notated music.

Working with clefs individually

Working with clefs by region

Working with clefs globally (by document)