The left hand position for holding the chromatic harmonica is identical to that of the diatonic, but there are two possible positions for the right hand. Some players prefer to control the slide with their index finger and use the position in the 1st photo. Others prefer to control the slide with their thumb and use the position in the 2nd photo. Experiment with both positions and use whichever is most comfortable.
As previously mentioned, by using the slide you double the number of notes available on the chromatic harmonica. The following example demonstrates the four notes available from hole number 1. The first note is an exhale note without the slide depressed (pushed in). This is followed by a different exhale note on hole 1 created by pushing in the slide.