I don't have a discord server sadly. Zinc in the Hole begins right after to complete the prologue (you'll know when you see the title card). The quest takes you to the next district. You'll have to get through that entire quest which includes two boss fights. Once you get to Zinc H.Q, you'll meet a specific character towards the end of the quest. From there on, it's pretty self explanatory.
She's a pretty tough boss, so you'll have to be ready. All together, it might take around 2 hours. The game itself takes around 15-20 hours to complete, so while it won't take ages to get there, it might take you a bit.
Eleanor's Dilemma, which is the side story you select on the main menu also features all size content, but it's rather short.