Yeah, this had me stumped too a few months back. It’s kinda strange how Logic handles EXS files.
Once you have placed the EXS files in the Sampler Instrument folder as outlined above, you need to click on 3 dashes above “Cutoff” in the EXS24 interface window. There you should see a drop-down menu with a list of the EXS instruments available and you can select and load it from there. If you don’t see your instrument there, click on ‘Refresh’ in the same menu.