On one island have a stock at least 10 of each the resources said in the description at the same time.
Fish - farmer level, no special requirement
Schnapps - farmer level, requires potato fertility
Bread - worker level, requires with grain fertility
Beer - worker level, requires both grain and hops fertilities
Canned Food - Artisan level, requires red pepper fertility
Most likely you have to transfer most of it to one island, and all those required fertilities rare on one island at the same time.
Same as console version.
https://www.trueachievements.com/a386676/winter-is-coming-ac...