NFT tutorial - Sell Order

Hello all

I can follow the full mutants YouTube tutorial and upload items via smart contract to OpenSea.

How do you actually go one step further to โ€œSellโ€ the items - I want all items at same price - without having to click on sell for each item individually?

Do you have to add a sell module to the initial smart contract along with the minting function, or can you do it another way?

Is someone able to suggest some code that they have used to do this.

Thank you!