This video is slightly outdated, but the general concepts are the same. The application interface has been updated since this video was published.
Assuming you've already connected a channel and added products, it's time to create a listing!
Remember, listings are created from products, not from other listings. So if you imported from a sales channel, make sure you've turned any remaining unlinked listings into products so you can get them onto other channels.
To create a listing, simply select the product(s) you wish to list within the Products page and click "Create Listings"
Using the drop down menu, select the sales channel account where you wish to create your listing, and follow the Listing Builder steps.
If you don't have a listing preset already saved, you will have the option to select your listing settings during this process. Make sure you name and save your options for later (this will save a listing preset for you)!
You will receive a confirmation that your listings are being created. When you close the confirmation window, you'll be taken to your listings page to see the status of that listing.