There's a few hints and tips for general board stuff here
And as for posting your avatar, you can't upload them as we already have a large bandwidth which is very expensive. You'll have to host it from somewhere on the internet or ask someone to host a pic for you. Once you have an image you want for your avatar, paste the image's address into the avatar option in My Controls
at the top of every page.
To post pictures, you click on the IMG
button at the top and paste in the address of the picture you want to post.
Hope that made sense. Feel free to pm me should you need anymore help.