The following is the owner's manual for your 2004 Dodge Neon:
P.99 describes how to load discs:
1. Select and press any numbered button without an illuminated light above it.
2. Insert the CD while the light above the chosen button is flashing and the two lights on either side of the slot are illuminated.
3. Upon insertion, the CD will begin to play, and both the button light and the lights in the corner of the loading slot will illuminate.
4. Repeat the process for loading any additional CDs. The CD playe rwill stop while additional CDs are loaded.
The radio will show the CD number, the CD track number, and the Track Time Elapsed while the radio is in the CD mode. IF more than one CD is loaded in the changer, the changer will automatically play the next disc after playing the last track of the current disc.
Wow, that's a lot of typing.
I didn't know the 2004 Dodge Neon had such a nice changer.