First, You must go to Episode 5: The Empire strikes back and enter the door to it

After entering The Empire Strikes Back you must go to chapter 2: Echo Base
(Make sure you have freeplay!!)

Playing the level in freeplay normally/getting the minikits until you get to this part
You must parkour on the platform by using the dark side of the force.
After parkouring and getting past/killing snowtroopers you will need to find a door that requires a droid

You have reached the gambiling spot and your done!
There are two in the room. The left one gives you a minikit in the main room and the right one (pictured) gives you a red brick also in the main room.