They will still sell the products they produce in a marketplace.
There is no rule that states they have to sell squat in a marketplace. They could, but they also couldn't. That's the whole point of the workers owning the means of production - the workers involved makes those deicisions, not a capitalist or bureaucratic parasite class.
Socialists don't hate markets, they hate workers not having any power or democratic choice in how they interact in the market.
Workers owning the means of production just means the workers are doing the same work but they are in ownership of the factory and the profits. They will still sell the products they produce in a marketplace.
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