Go to your OpenSea profile by clicking on your profile icon on the upper right corner and scroll down to view your artworks. Another way to view your artworks and collections is to click on "Create" in the upper right corner and then "My Collections".
Once inside your collection, click on the work and click on "Sell".
You can now decide how to sell your work: You can choose between setting a fixed price ("Set Price") or start an auction ("Highest Bid").
If you set a fixed price, you can insert it in the "Price" tab. If you prefer the auction, you will be able to set the minimum price, the reserve price and the length of the auction.
For works sold through auction, you can accept an offer anytime. When the auction ends and there are offers above 1 ETH, the highest bid will win the auction. If the offers are below 1 ETH, the seller can decide to accept the highest offer or not.
The last step is to set the bounties. OpenSea will automatically receive 2.5% bounty. In order for Artland to receive the same bounty, you need to click on "Edit" and drag the bar to 2.5%. The author of the work will also receive a royalty, if they have defined it when creating the work.
By clicking on "Post Your Listing", your work will be for sale. However, remember that you need to have sufficient funds in your wallet to be able to pay for the gas fees for initialising your account and, consequently, set the work for sale.
Please, check this article to understand when the seller has to pay gas fees.
Now your work is on for sale. Remember that as a user, your work cannot be uploaded on Artland, therefore it will be for sale on OpenSea.io only.
Once your work has been sold, you will receive a confirmation email from OpenSea.