You can buy copies of the print edition of your book directly from Amazon at a special, low author's price. You don't get royalties for these copies, and copies bought this way don't affect the book's Amazon sales rank.
Here's how to do it.
First, log into your KDP account. This uses the same login information as your Amazon account, but you have to use this URL: https://kdp.amazon.com
Once you are logged in, you should be on what's called your Bookshelf. If you are not on the Bookshelf page, click the link labeled Bookshelf near the top of the page. That will take you to your Bookshelf.
On the Bookshelf you will see all of your books listed. For each book, on the left are the book's cover and title. To the right of the book's cover and title is the word Paperback. To the right of that is a rectangular gray button labeled Order author copies. Click on that button.
You'll probably be asked to log in again. I suppose this is a safeguard.
Once you have logged in again, you'll be on a page for ordering author's copies. You can enter the number of copies, and you also have to choose your Amazon marketplace. That refers to the Amazon site that you normally use. For example, if you're in the US, you'll choose Amazon.com. If you're in Germany, you'll choose Amazon.de.
Once you've done all of that, click on the yellow button labeled Submit Order.
What follows is similar to ordering anything else on Amazon. When you're done, you're told that the copy or copies you ordered will show up in your Amazon shopping cart. Sometimes, they show up there immediately, but usually it takes a few hours. You should get an e-mail telling you when they do. You can wait for that e-mail, or you can periodically check your Amazon shopping cart. Once the book's copies are in your shopping cart, you will complete the order in the way you normally do on Amazon.
Note that the shopping cart is part of Amazon itself, not KDP, so here I'm talking about logging into Amazon itself at https://www.amazon.com
If you have an Amazon Prime membership, it doesn't apply in this case. You have to pay shipping, and the books usually take a while to get to you.