Play the first note of the scale, Middle C, on the trumpet by holding no valves down and blowing into the mouthpiece.
Play the E-flat on the trumpet by holding the second and third valves of the trumpet down and blowing.
Play the F on the trumpet by holding the first valve on the trumpet down and blowing.
Play the F-sharp by holding the second valve down on the trumpet and blowing.
Play the G note by holding no valves down and blowing. Tighten your lips to ensure that this note is higher in pitch than the first open-valve note you played, Middle C.
Play the B-flat by pressing all three of the valves down and blowing into the mouthpiece.
Play the final note of the blues scale, C, by holding down no valves and blowing into the mouthpiece. This final open-valve note should be higher in pitch than the Middle C and G which you played previously in the scale.