Hello Instructors

Im currently reading Tarot & Kabbalah. I understand that the Ain is the unmanifested absolute. Beyond everything, any form, Gods..etc. And the Ain Soph is were all creation emanates from.
My question is how did Ain Soph came to be? Is it a manifestation of the light within the infinite Darkness of the Ain? But why? How did Ain Soph become something other then Ain... Hope i make sense...

Thank you in advance