Need help with mask

[DanielG]

The mask attack is explained on https://hashcat.net/wiki/doku.php?id=mask_attack

For example, if you want to test 4 letters with only one capital letter and 3 lowercase letters, then your masks are:

?u?l?l?l
?l?u?l?l
?l?l?u?l
?l?l?l?u

first line has capital letter as first, second at second position, etc.