This is actually a new feature in Galaxy S8 and S8+.
This Galaxy S8 guide first shows you how to use Galaxy S8 apps screen with gesture. Then the guide explains to you how to show apps button and how to hide apps screen button in Galaxy S8 and S8+.
How to use gestures to access Galaxy S8 apps screen?
When you get you Samsung Galaxy S8 or Galaxy S8+, you will find there is no apps screen button (app drawer button).
Then you may wonder how to access Galaxy S8 apps screen (apps drawer).
Of course, the apps screen button is just hidden. You can enable the setting to show apps button (read on).
The gestures you can use to access Galaxy S8 apps screen include is just a swipe.
Swipe upwards from bottom part of the home screen as shown below.
This will bring up the apps screen (app drawer) in Galaxy S8 and S8+.
Once in apps screen of Galaxy S8 or S8+, you can swipe left and right to scroll apps screen panels as you did in previous Galaxy phones.
If you swipe up again in the apps screen, you will be brought back to home screen.
In other words, the swipe up gesture will cycle you through Home screen –> Apps screen –> Home screen –> Apps screen—>.
Another way to return to Home screen is to press Home button or Back button.