When people arrived in Auschwitz how were they registered?

Upon arrival at Auschwitz, individuals were subjected to a brutal registration process. They were stripped of their belongings and forced to undergo a medical examination, after which they were assigned a number that replaced their name. This number was tattooed on their arm as a permanent identifier, marking them as prisoners. Many were then sent to the gas chambers or forced labor, depending on the selection process that took place upon arrival.