To send a PM (called "conversations" here),
1) Hover over the person's avatar you want to converse with and click "Start Conversation" button.
OR
2) If you want to converse with more than one person, click on the little envelope (Conversations) link in the upper right, by your username. Then click on the "Start a new conversation" link. You can put in multiple usernames to converse with there.
To add a profile picture - I'm figuring you mean an "avatar":
1) click on your username in the upper right, then click on the lower half of the avatar circle in the upper left of that window. Follow instructions for inserting picture.
OR
2) click on your user name in the upper right, then click on "Account details" link. The third thing down on that page is "Avatar", follow instructions there.
BTW, when you posted that you were 2 hours short of the 24 hour minimum necessary since joining for the options to open to you.