Understanding the Regex code I have been given

Hi, Qualtrics support suggested I post here.

I'm setting up a survey that changes a password and I'm using regex to authenticate.
Someone has given me this string and I need someone else to translate it for me so I can understand what it is looking for, so I can tell people what they need to include in their new password. Can anyone help translate this string?
The string is: /^(?=.*[A-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[$@])(?!.*[iIoO])\\S{8,12}$/

Many thanks in advance for any assistance you can give.