You may have just read the title of this post and stormed immediately to the comments, about to write an essay about how Android Police is just fishing for page views. Surely there's no need for an article about how to take a screenshot, right? Actually, in this case, yes. Taking screenshots on the Galaxy S8 requires a different button combination than previous models, causing confusion for some buyers.
Previously, taking screenshots on Galaxy devices involved pressing the home and power buttons at the same time, much like on iOS. However, the S8 has switched to the more common combination of Power + Volume Down. This probably makes switching from most Android devices easier, but someone transitioning from the S7 (or earlier) might be a bit confused.
If pressing physical buttons is too much work, you can always hold down on the home button to open Google Assistant, and press the 'Share Screenshot' button. The S8 also allows you to take a screenshot by swiping the edge of your hand across the screen (while still keeping it on the screen). Plenty of options for your screenshot-taking needs.
Once you actually capture it, the S8 has a neat feature you can use called Scroll capture. Like several browser extensions, this scrolls down whatever content you are viewing and adds more to the screenshot. Honestly, I wish stock Android had this feature.