How do you put midi in your quest

Click the quest menu and go down to midis.

Now, select a slot to edit... then click load (or something like that). Now, you can mess with the loop options or the volume.

It is also a good idea to make a backup of your quest before adding midis. I once added a midi and my quest got corrupted and I couln't use it anymore.

Yup, that's true, VEL.
Remember to put your MIDI volume to 255, most people leave it a 144 and then it's so low that only the SFX can be heard (almost).