How to use "Cruise Mode" feature?

Hey guys, I would like to try out the cruise feature but having an issue getting started.

So when I open Traktor I am seeing first screenshot, next I try to load a tune into Deck A but seeing 4 slots so I choose Slot1. Problem is when I click the Play button the track does not play, it only highlights Green color. The right deck plays as normal so what's the issue with Deck A please? I am not understanding why those 4 slots are showing in Mixer view?

I am following this tutorial here step by step:



I am thinking maybe it's the Playlist step where I might be having problems. When I select Playlist from the left pane, I navigate to my mp3 folders on my hard drive to add one folder. Am I supposed to create a Playlist in Traktor for all of this to work please? Thanks.