Start here:
https://fineartamerica.com/showmessages.php?messageid=3565122
The short answer is:
1. Know who you are as an artist. What do you create and why do you create it? What void are you filling in the art/photography print market? What problem or need are you solving? What is your mission as an artist? If you can't answer those, you're not ready to sell.
2. Build a portfolio of images that are high quality, interesting, and suited for the home decor market. Many photographers here have portfolios of thousands of images. If you have a style, or a specific niche you specialize in that may help you, but you had better be skilled at it. High quality means high resolution images, composed and cropped well, appropriately adjusted and saved for upload and print.
3. Determine who your buyer is. Who wants your images? Age group? Economic group? Professions? Do you want to sell worldwide or just in the US?
4. Where are your buyers? Are they on social media? Are they in real life galleries? Do they read blogs or art magazines? How do you reach them?
5. Get your work in front of your buyers and build an audience. Build an email list, build a following. Then you must send potential buyers to your sales page. This can be done in real life, through email, through social media, in groups, at trade shows.... this part of the process can take years, but it's the most important part.
6. Keep making high quality work and building your audience and showing them what you do.
If it sounds like a lot of work, it is. It's a very competitive market. For many of us, it's a full time job and then some. If you expect just to upload and sell you'll be sorely disappointed.