Everything is made out of one single elephant trumpet.
The main pad that plays the chords is just a few audiosamples from the middle of the elephant trumpet looped over and over in a sampler. Basically it's just a tiny tiny little portion of the trumpet sound. It's barely a few milliseconds long. There's some chorus and lots of reverb, and the attack and release are quite high.
The bass is the same thing, just filtered so that only the very lowest frequencies come through. Then some more filtering and distortion and compression to get it to actually sound bassy.
The high pad note is the middle bit of the same elephant sound stretched out a lot. I believe I stretched out the sound to be over a minute long.
The blips that come in half way through is literally just a second or so of the actual elephant. I just tuned it correctly, added some glitchy delay and reverb, and filtered it so it wasn't too bright.
And the elephant sounds are just... well... the elephant sound.
So overall it's pretty simple!