When you create an EXS24 mkII sampler instrument using Auto Sampler, the default location to which the sampler instrument is saved is Audio Music Apps > Sampler Instruments > AutoSampled Instruments. Sampler instruments saved to this location are available in the AutoSampled Instruments submenu of the EXS24 mkII Instrument pop-up menu. You can choose a different location to save the new sampler instrument, but it might not appear in the Instrument pop-up menu.
The samples are saved to a folder in Audio Music Apps > Samples > AutoSampled > [the name of the EXS24 mkII instrument]. Inside the folder, the individual samples are saved with the following naming scheme:
<EXS instrument name>–<note >–<velocity>–<4-character suffix>
After creating an EXS24 mkII sampler instrument using Auto Sampler, you can work with it the same as with any other sampler instrument. For more information, see the EXS24 mkII chapter of Logic Pro X Instruments.