Does anyone know how I can transpose music written for Eb tuba in bass clef, to, Bb Bass in the treble clef?
You can change the clef either before or after the transpose, but I would transpose first using Tools | Transpose, then change clef using the Change Clef Procedure (https://noteworthycomposer.com/composer/faq2.htm#newclef).
Note that tuba music in bass clef is usually CONCERT PITCH,
regardless of the key name of the instrument. The treble
clef music is typically transposed.