Okay, you've got 3 short novels ready to go and you're chomping at the bit to get them out on the street selling themselves like the good little hookers they are.
First, don't do it immediately unless you're absolutely committed to self-publishing.
Why not take the time and send them out on the submission trail first? In the meantime, you can get cracking on your next novel. Nothing ventured, nothing gained, right?
Second, set everything aside for at least a week. Do not even look at these books in that time. When the week (or three) is over, look at the first one again. Give it a good going-over. Hand it to a disinterested beta-reader and have them read it too. Hand it to someone who's willing to edit it for you. Do this with each successive book. In the meantime, keep writing your next book.
Third, unless you know GIMP or PhotoShop or some other image manipulation tool, hire someone to do a good cover for your books. Prepare that cover to be used when you upload your first book. You'll need it immediately.
Fourth, when and if you decide to self-publish your books, after you've done everything outlined above, and I do mean everything, space your releases out over a few weeks to a few months. One book a month is good. It will allow your readers to finish one book and decide if they want to read the next one when it's released. There's nothing wrong with building a little reader anticipation. This kind of release schedule also allows you to write a few shirt stories as "filler", work on your next book, and do some marketing.
Last, have a plan. Decide what you want to do with your writing. Are these 3 books it or do you have short stories and more books in you as well? With these 3 done, if you have more, you need to get working on the next right away. But, in addition to this, you need to figure out what you really, really want to do and build a plan for your future. As a self-publisher you are now a business. Businesses need to have business plans in place. Those plans change, but at least next year at this time you can compare where you are then to where you are right now and see where you want to be the year after that.
I've been doing the self-publishing thing myself on Amazon for just over a year now. My other experience extends back better than 30 years in various aspects ranging from newspapers to desktop publishing to self-publishing gaming products. My advice is "Do as I say, not as I do."
Whatever you decide, you'll have questions. That's what the AW community is for. Use it and listen to it. There are a lot of real experts here (I ain't one of them).