we're going to Guitar Center to buy a midi to usb cable
I realize that the people at GC have to make a living, but it's possible that what they sell for
$29.99 is not worth six times more than what you might be able to get for under
$5 elsewhere.
On the other hand, getting it right away is nicer than waiting for it to be shipped from China, and it's also nice to be able to return the thing (if it doesn't work for whatever reason) just by walking in.
if it doesnt recognize this right away, do I need to download any drivers?
The devices we're talking about don't include drivers, and shouldn't need any drivers that are not already a standard part of your Mac OS.
You connect the device to your computer (via USB), and its power LED should illuminate. Then launch Audio MIDI Setup. It's here:
Macintosh HD/Applications/Utilities/Audio MIDI Setup
In Audio MIDI Setup, look for where it says "MIDI Devices," "MIDI Window" or "MIDI Studio" (the exact words might vary, depending on the version of your OS). In the MIDI Window, an icon representing your midi adapter should appear automatically. You shouldn't need to change anything in there. You're just taking a look to verify that your Mac sees the device.
You probably won't need it at all, but extra information about Audio MIDI Setup can be found
here,
here and
here. Those links explain how to do various things you probably will never need to do, but it might be interesting background, and certain ideas might be helpful later. The program also has a good help system.
From there we go to the EX24 in Logic yes?
That's probably a good place to start. You could load the EXS24, and load a drum kit in it. Make sure this track is selected, and this will automatically make it record-enabled. Now hit pads, and you should see midi activity in the Logic transport bar (in the place that says No In - No Out when the system is idle). And you should hear sounds.
It's also a good idea to verify that you can make sounds by using the Logic Caps Lock keyboard to play that EXS24 kit.
Let us know how it goes, and then we can deal with other questions that will probably pop up.