Change refers you to the changeless.
Your night dreams refer to the changeless dreamer and not to the dream characters that appear and disappear.
To comprehend the unmoved, first you need to contemplate stillness and dispassion.
Contemplate that which is unmoved in your experience. Contemplate the permanent.
If you remain enamored and hypnotized by what appears, you will be the prey of your thoughts and feelings.
You will be like a yo-yo trying to find peace and balance in that which cannot provide it.
Find that which is unmoved and unchanged in your experience.
Then you will know the peace that is beyond the mind.