How to create a masked attack?

[sky]

I am an absolute noob at brute forcing, but I need to get 4 MD5 hashes. I have been searching the forums but I don't understand what the answers are and how to apply that, so please keep in mind I am a noob.

I know the 4 passwords I am looking for have 1 uppercase and are 6 chars long. I personally suspect they have no special characters but I don't know.

How do I brute force using this specific thing? I understand I need a mask, but how do I get it / make it?