After years of having a dedicated home button and physical navigation keys, Samsung ditched its traditional layout for a more modern, virtual approach on the Galaxy S8 and S8+. As a result, you can now customize the navigation panel along the bottom of the screen.
To get started, give the notification bar a tug and tap the gear icon in the upper right corner to open the Settings menu.
From there, tap on "Display."
Scroll down about three-quarters of the way in this menu, until you see the "Navigation Bar" option. Tap it.
This menu is simple, with just a handful of options. You can set the color in the first section---there are a few pre-selected colors right off the bat, but you can tap the last one (the multi-colored circle) to select any color.
You can also choose to unlock the phone with the home button here, just like on past Galaxy devices. This is actually a pretty interesting feature with the transition to virtual buttons---Samsung has done an excellent job of retaining a lot of the functionality former Galaxy users like from the physical home button. That's good design.
Otherwise, you can also change the button layout here, opting for the more traditional Back-Home-Recents layout, or sticking with Samsung's Recent-Home-Back option. This is easily my favorite thing about the virtual buttons, because I much prefer Android's default layout to Samsung's. You do you, though.
Lastly, you can choose how hard you actually have to press the home button for it to qualify as a "hard press." The stock setting is probably fine for most people, but again, it's cool that there's a tweak here if you need it.
While simple in nature and use, this is actually a huge transition for Samsung---and a welcome one, too. This puts the Galaxy S8 and S8+ more in line with other Android phones, offering a more stock-like look and feel.