1. Introduce yourself. Maybe say why you're here?
2. Look around, read anything that's interesting to you.
3. Continue with 2 until you feel like you have a sense of the culture of this forum. I don't mean Deaf culture exactly, but specifically AllDeaf culture. See how people react to things other people say here, etc.
4. Start posting. Maybe something someone says makes you think of something you'd like to add. Maybe you'd like to start your own thread about something you want to talk about here. Also, continue with 2. It's pretty intuitive.