After combining your exposures (or, operating on a single exposure) you can run the xtellcor program from spextool to perform telluric corrections using your A0V star.
At the IDL prompt, type
IDL> fire_xtellcor_ld
This will launch the xtellcor GUI. Enter in your "Object/Spec_xxxx.fits" files or combined files in the appropriate boxes, and then follow the instructions provided with spextool to complete the telluric and flux correction (these operations happen simultaneously).
The full instructions can be accessed by clicking the "help" button at the bottom of the xtellcor window. Note that if you used the FIRE telluric matching code at Magellan, you can be guaranteed that your telluric star is an A0V and hence will work with xtellcor. If you prefer to use G stars or some other flux calibrator, this software will NOT work properly.
At present we have not written the equivalent of fire_xtellcor_ld_finish. This is on our to-do list but in the meantime you can use the regular / general xtellcor routines to flux all of your data.