Bernice: I give you an example :
You got 6 dice with the value 1,
you got 6 dice with the value 2,
you got 6 dice with the value 3,
you got 6 dice with the value 4,
you got 6 dice with the value 5,
you got 6 dice with the value 6,
You got all the values so you got this achievement.
For example : before the achievement, you didn't get 6 dice with the value 3, but you certainly got 6 dice several times with the value 6.
Do you understand now ?