Welcome to Planet Tolkien, Valernil thalion. :wavehello:
20 mithril pieces are awarded to your account every time you go to your account homepage. At the moment the only thing to spend them on is Private Mails to other members, although eventually there will be many more features involving mithril available.
If you need help around the site, I'd suggest either trying the Help menu on the left hand menu bar, or looking through the Help section of the forum board above incase your question has already been discussed. If after that, you are still unsure, find what you think is an appropiate place and ask what you need specifically. Someone will eventually come along to help you.