I second the recommendation for gamefaqs. If you want something more vague than a walkthrough: all I remember is that you had to use the crane and that drill thing you get from Chepito (the Bust-All?) to do just about everything there. There’s some bit where you had to go inside and get Mercedes’ stockings, but I can’t remember if that’s an unrelated puzzle.
If it’s any consolation: I scripted that conveyor belt sequence and remember its being a total pain in the ass, much like all of Year 3 with the voice effects and the pulling-towards-the-end-of-the-world animations, and I can’t remember how the puzzle works. So there’s no shame in using a walkthrough. Neat game, in retrospect, but the puzzles don’t make a damn bit of sense.
And if you’re already there, I’m assuming you’re playing with the patched version. If not, find the patch or everything’s unnecessarily hard. There’s some nightmarish puzzle with a forklift in an elevator (Year 2?) that took me a week to get working, only to discover that anyone playing on a machine faster than my 450 MHz one couldn’t solve it because I didn’t make the scripts use the system clock correctly.