Your password should be between 8 - 12 alphanumeric, include 1 number & 1 alphabet. What does it mean?
This means that your password must be of at least 8 alphanumeric character and can reach to maximum length of 12 alphanumeric characters. The term 'alphanumeric' means the combination of upper-case and lower-case alphabets or letters and numbers and special characters (such as @, #, $ etc.). From the conditions given, an example of password could be formed as following: