Bajin's trades starts with Bajin in Inside Yuno (100, 153). The steps below are read from the quest's script on this server, in the order the script's quest stage moves through them.
Not confirmed yet: parts of this quest could not be read with certainty from the script; they are marked at their step.
Walkthrough
1 Talk to Bajin in Inside Yuno (100, 153)
When Room in your inventory for what you get; Script check: .@kyulkwa < 4 || .@kyulkwa > 8 Have with you 1 × 
Mixture, 5 × 
Mini Furnace, 5 × 
Coal, 5 × 
Burnt Tree, 5 × 
Fine Sand, 3 × 
Rough Elunium, 3 × 
Rough Oridecon, 2,000 zenyIt takes 1 × Mixture, 5 × Mini Furnace, 5 × Coal, 5 × Burnt Tree, 5 × Fine Sand, 3 × Rough Elunium, 3 × Rough Oridecon, 2,000 zenyHold on for just a second!
*Vrrrmrmrmrmrmrmrmrmrmrmmmmm*
*Pakakkakakakkakaakapakakkakak*
*Shakakakakkakakakakkakakakakka!*
Not confirmed yet: gives an item the script computes (getarg(0) x getarg(1)).
Script:
npc/quests/quests_yuno.txt:655
How this page is made: every step comes from the NPC scripts the server loads for Episode 13.2 (the file and line are under each step). "When" lists the checks the script makes before that branch runs; "Have with you" are the items it counts; experience from getexp is multiplied by the server's 50x quest rate. NPC lines are the script's own text.