Bass clarinet sounds a Major-9th (an octave + a whole step)lower than the written note. It plays in the key of Bb, and it reads in treble clef, just like Bb soprano clarinet.
The fingerings are the same, with the exceptions of notes below low-E and notes above high-C. For example, the low-C below the staff is "thumb-1-2-3", just like the same note on soprano clarinet. Good luck!

BH

Yep, I played bass clarinet in college. Bass has one extra note below the lowest E. Some of the expensive pro models with a "Low-C Extension" will play the C below the 4th ledger line under the treble clef.

What kind of ensemble do you have?

http://www.wfg.woodwind.org/clarinet/basscl_alt_1.html

this is a fingering chart for the lowest range of a bass clarinet- it has the standard low-Eb as well as the notes on fancy low C models if that pertains to y'all's instrument.

As for your player being able to "magic" a sound out of it, it shouldn't be too hard for a clarinet player to get a sound out. I switched from soprano clarinet to bass in 7th grade and was able to play it right away. Remind the player that because the instrument is larger, they will need to use much more air!

Getting the sound out isn't hard- it's making that sound worth playing that might take a little work. Good luck, a bass clarinet is a worthwhile addition to an ensemble! (granted I'm probably biased)

Great fingering chart, Laeta. Thanks!