The Forum Policy is located in the Player Guide as Chat, Forum, & Wiki Policy.
After you’ve made an account, you can post by hitting the reply button or the box that is at the bottom of the thread for a quick reply.
Yes, it needs to be considered a safe for work image (sfw). And it has to be 90 by 90 pixels in size, and can only be a max of 6.00 kiB.
Yes, again it needs to be a safe for work signature.
No, you only need and only should make one.
This should be your OOC handle.
Those are Forum Private Messages, this is a good way to reach out to an ST or an Admin.