Changing bass key

i see bits and pieces about this everywhere and cannot find a clear set of directions on how to do this. I play everything in Eb and need to change almost every bass and drums song. I’m sure it’s right in front of my nose but I can’t figure it out. Can someone point me to the instructions? Please and thanks you!

Its a learning process. It will start with exporting a midi file. Then opening that midi file in a midi editor where you can see the bass notes. Then you highlight all the bass notes and drag up or down to find your key. I think most people call this software DAW (Digital Audio Workstation) but I know BB itself has an editor built in. I would keep reading all the posts here I am sure you fill find a process that works best for you.