Greetings and welcome to the watercooler
Take a wander around the various forums, there's lots to see and lots to learn, and even some fun threads too. Come along and pop on over to the Traditional Irish Pub (at the top of the Newbie forum) and say hi, there's plenty of friendly faces that you can chat with and lots of banter. There's also the Question of the Day threads at the top of the Newbie forum where you can answer random questions.
Don't forget to read the
newbie guide, and if you want to know what all the buttons mean check out
this thread.
P.S. About the avatar. You can have a custom avatar straight away, however, it is small. When you reach 50 posts, you are allowed a bigger one.