Portrait and Signature?

I've gone to my profile and clicked the "customize my profile" button; what I found was a pop-up list of incomprehensible font settings. I just cannot find a way to change my profile picture or to write a signature to go after my posts. Are those things limited to people who have been around a while, or have posted a certain number of posts? Or am I just stupid?

Its under settings, not my profile. Once you click settings you will see on the left the options for profile picture and signature.

Wow, there it is! Thanks so much!