It takes me like... 20 minutes to figure out how to do it each time.
Easiest way to figure it out is hit "report concern" and ask them. I tried to figure it out for you but I got no sleep last night and can barely function today.
Click on "welcome" in the upper left corner of screen
click edit
then click user profile
scroll down and choose your file, click upload
scroll down to bottom of page and click submit