You can upload a avatar(ava) But because you are non-premium must be 150x200
Your signature(sig) must be 600x300, (It's the image/gif at the bottom of our comments.)
To give reputation(rep) click the black star below your status/green rectangle. It can be positive re or negative rep.
You don't nacessarily have to make your own ava/sig. You can find some people have already made some here:
You must be registered for see links
If you look further you see that you can request avas/sigs and more!