Please follow the below method to enable gallery labs on any Samsung phone running one UI
Open the gallery and click on settings
Scroll down and click on about gallery
Keep tapping on version number till you get a message the gallery labs has been enabled. (7 to 8 taps)
Go back and you will find a new option of gallery labs below about phone. Here you can enable the new upcoming features.
Attached are the screen shot for your reference
