All right. This is a very "basic" (albeit tedious) way to trigger your own sample using the EXS24 sampler:
1. Choose the track you want to "replace", for example, a kick or snare track. (one at a time though)
2. Underneath that track (in the arrange window) create a software instrument track, but leave it blank for now. It'll be used shortly.
3. Select the audio region for your kick or snare track and double click it. This should open up that region in your sample editor.
4. In the sample editor, choose the Factory drop down menu and select Audio to Score.
5. This will open up a box with a few parameters you can tweak. The main parameter you will be concerned with is called...well I forget what it is called but it basically controlls the sensitivity of what items from the audio region will be scored out. It won't be too hard to find. This step is important though because often times there will be kick or hi hat bleed in a snare mic. If this process is set at maximum sensitivity then those transients will be triggered when we set up our sample.
6. Once you have your settings, choose Process. This creates a score from your audio region, and a midi track. You may have to move the midi track down to your software insturment track you created in step 2.
This is where things can get tricky. If you open up your midi view aka piano roll, you'll see that the midi notes are all over.
7. Open up your Event List editor. This is done by choosing List from the top right area of the main window.
8. Here you can move all the notes to one single note. If it's a snare track you are replacing you probably want to move it to D1 or E1. This is what you do
Select the very top midi note event in the Event List. Change the Note option to D1. Just double click the area and type D1. Now press Shift-V. This is a little shortcut that should change ALL of the notes in your Event List to D1.
Now do the exact same thing for the Channel section in the Event list. You may notice that some may say Channel 1 and others are channel 2. Change everything to Channel 1 in the exact same way.
9. Now you have a midi track with your snare hits all on one note. In the Event List windo you can play around with note velocities if you want.
10. Once your velocites are set, it's time to load our sample. Go to the software instrument track that we created, and where your new midi track should be, and load the EXS24 Sampler into the Instrument slot.
11. If you want to use a snare sample from one the default sets, load a default kit into the sampler. This is why we moved all the midi notes to D1. D1 is a snare sound by default.
Play around with kits/samples until you find something you like. Unfortunately you may run into phase issues if you have your original snare and your new triggered snare playing at the same time. There is no way to counteract this easily unfortunately. This is the best method I've found to replace drum hits in Logic.
If you have anyother questions please let me know. I will be happy to help. If you want to load your own snare samples (meaning ones not from a default EXS24 kit) that can be a tricky process and will require another little walkthrough. Let me know. Hope this helps and I hope you can understand it well.
I still recommend drummagog.