Unless you want to have it be a little more special, then you could go with they said. However, if you're talking about when you have 3 music loops and want them to play, but not to interrupt each other, you can do it this way. Make sure you understand death counters though:
TRIGGERS (FOUNDATIONS):
Conditions
========
- Computer Player suffers at least 1 death of Hatch (UNUSED)
Actions
=====
- Add '1' death of Hatch (UNUSED) for Computer Player
- Preserve Trigger.
Now, you will require a switch for each wav loop. For your case, three. We will name these switches 'wav1', 'wav2', 'wav3'.
(For first wav)
Conditions
=======
- Computer Player suffers at least '(However many deaths it needs until the end of song)' of Hatch (UNUSED)
- Switch 'wav1' is set
Actions
=====
- Play 'wav1.wav'
- Set deaths of Hatch Unused for Computer Player to 0
- Preserve Trigger.
(For second wav)
Conditions
=======
- Computer Player suffers at least '(However many deaths it needs until the end of song)' of Hatch (UNUSED)
- Switch 'wav2' is set
Actions
=====
- Play 'wav2.wav'
- Set deaths of Hatch Unused for Computer Player to 0
- Preserve Trigger.
(For third wav)
Conditions
=======
- Computer Player suffers at least '(However many deaths it needs until the end of song)' of Hatch (UNUSED)
- Switch 'wav3' is set
Actions
=====
- Play 'wav3.wav'
- Set deaths of Hatch Unused for Computer Player to 0
- Preserve Trigger.
TRIGGERS (SECOND FOUNDATION FOR STARTING AND IDENTIFYING LOOP)
Now, when you need to have a certain loop start playing, you need to have these conditions and actions along with the trigger.
Conditions
=======
- Whatever conditions you want
- Computer Player suffers exactly 0 deaths of Hatch (UNUSED)
Actions
=====
- Set Switch 'wav1/wav2/wav3'
- Set 1 deaths of Hatch (UNUSED) for Computer Player.
- Preserve Trigger.
Sorry if this is too much.

(I think it is)