Actually that mouthpiece looks very small i am wondering if you did not actually get a french horn bugle. If it is not a fh bugle than it is really a baritone bugle, not a bass, I would believe.
The horn is upside down in the picture, You hold the horn with the right hand and play the piston with the right thumb. That is your first valve or whole step valve. The left hand works the rotor and that is the half step valve or second valve. The horn is in G so your open notes would be G,D,G,B,D,F, hi G, although they were notated in treble clef like trumpets, c,g,c,e,,g,Bb, hi C.
have fun
ken k
