What you get
One folder per instrument. Inside it are the .exs instrument
file and the WAV files it uses.
Kit Name/ Kit Name.exs Kick 01.wav Snare 03.wav ...
Each sample reference inside the .exs carries a filename and
the folder it was written from. Logic resolves the samples by name when they
sit beside the instrument, so you can move the whole folder anywhere and it
still loads. What breaks it is separating the two.
Where it goes
Logic looks for instruments in:
~/Music/Audio Music Apps/Sampler Instruments/
Copy the exported folder there. Logic reads subfolders, so the instrument appears under its own folder name rather than loose in the list.
Loading it
Add a Software Instrument track, load Sampler, then pick the instrument from the library menu at the top of the Sampler window. If Logic was already open when you copied the folder, the list refreshes when you reopen that menu.
If samples do not load
The usual cause is the WAV files having been separated from the
.exs. Logic finds them by name in the instrument's own folder,
so the two have to sit together. Put them back rather than relocating samples
from inside Logic.
The format itself
This guide covers getting the file onto your sampler. For what is
actually inside a .exs, what else reads it and where its limits
are, see the Logic EXS24 instrument format.