Samples are converted into MODX Waveforms. You actually direct the .wav/aiff data to a Key (which can be set to trigger the audio at original pitch). If you place this Waveform in a Normal AWM2 Part, you can set a range of Keys to trigger the playback, a Velocity Range to which it responds. As few as one and as many as up to 256 individual audio samples can be configured in a Waveform.

Each Normal AWM2 Part can reference 8 Waveforms, one each from its 8 Elements. The “Element” is a set of parameters that instruct the audio how to playback. It is here you can apply pitch change, timbre change, and amplitude (loudness) change over time (Envelope).
Each Drum AWM2 Part can Reference 73 Waveforms, one each from its 73 Drum Keys, C0~C6. Drum Envelopes differ from Normal Envelopes in that you do not have to hold the key down for the audio to play in its entirety. In a Drum Kit Key you can set “Receive Note-Off” = Off... thus allowing you to create an Amplitude Envelope that can support playback of the entire duration.

In other words, you expect to hold down a key on a Normal musical instrument sound to sustain its Envelope. Drum Envelopes can be set to ignore Note-Off allowing you to trigger the entire sound without having to hold your finger on the key.

Therefore, the answer to your question is to access your Waveform through a Drum Kit Part — it is here you create the Envelope that you need to play the entire audio clip from just a trigger event... the entire audio clip can be made to play without holding down the Key.

If you’ve already loaded the audio... simply access that User Waveform from a Drum Kit Part
If you are loading the data, load it directly to a Drum Kit — targeting a specific Key in that Kit.
Above I've loaded a .wav to C1 of a Drum Kit. I've set it to "Assign Mode" = Single (once instance of the audio can play at a time). I placed it in a GROUP (Group 1) - when the audio is a loop you can have it play until another KEY in the same Group is played. You can create the AEG by touching "Level" and setting an Envelope to support your Audio clip. Drum Notes can be set to Decay 2 Time = HOLD

Shown below is the EDIT WAVEFORM screen of a .wav when loaded

Extra Credit:
The AEG (Amplitude Envelope Generator) for a Normal AWM2 Element consists of the following components:
Initial Level
Attack
Decay 1 Time
Decay 1 Level
Decay 2 Time
Decay 2 Level
Release Time

These are the parameters that the synth uses to describe what in old analog synthesizers was referred to as the ADSR (Attack-Decay-Sustain-Release). It uses a series of TIME and LEVEL settings to describe the loudness shape of the sound.
Time = how long it takes to travel - the higher the value the longer time it takes
Level = describes how much - the higher the value the more Amplitude.

The AEG for a Drum AWM2 Element is a bit simpler:
Attack
Decay 1 Time
Decay 1 Level
Decay 2 Time

In the first example below you see a graphic that describes a DRUM or PERCUSSION envelope. In the second example, you see a graphic where the DECAY 2 TIME is set to 127 or HOLD - the envelope is set to play indefinitely. The Drum Key parameter is set to ignore Note-Off (Receive Note-Off = Off)

In the third example, you see a typical musical (Non-Drum/Percussion) instrument described. Notice Key-Off is used to describe when to proceed to the Release Time ... “Release Level” is always eventually 0.

I am speechless. I am without speech :))
Thanks a lot for the detailed explanation, it works.

I'm here because I need to trigger a vocal sample by smacking a key and then getting my left hand back up, not waiting around to hold the key.
This tutorial is incredible. I was just about to use the Key Off function and call it a day. I hadn't even thought about making it a drum part.

After spending 7 years with Bad Mister's expertise on my MOXF and now being able to use the amazing touchscreen of the MODX.
It's so much easier!

Bad Mister is a huge asset to Yamaha synths! I bought the Discovering the MOXF DVD back then and it helped a lot.