TromboneChat

How do you learn/teach fingerings in different keys; for example tuba in Bb, C, Eb and F?

Because I have bought C bass trumpet, I have tried thinking in C, but always end up transposing the notes whole step and using Bb fingering. My fingers have already remembered the Bb fingering and move by muscle memory. Sometimes I can’t even play recorder .

There isn't a quick fix, you have to build up the muscle memory and brain to hand relationship the same way you did with Bb fingerings: scales, arban book, practice. Go back to the beginning.