Producer name: use the form on the label (e.g. "Château Margaux" not "Margaux"). The ID is auto-generated as a URL-safe slug of producer + wine + vintage.
Vintage: four-digit year, or NV for non-vintage (mostly Champagne).
Adding a new region? You must first add the region to regions.json with its lat/lng centroid (the region's geographic heart — usually the main town or vineyard concentration). The form will block submission until that's done, since without coordinates the pin has nowhere to go.
Adding a new grape? Just type it. The form will generate two JSON snippets — one for wines.json and one for grapes.json under additional_varieties. You must pick a colour manually for new grapes since auto-detection only works on known ones.