To add a signature you must go to your account settings.
Click your name. Look for the little wrench symbol and click on that. Then click on forum settings. There should be " signature" link you can click on. It will let you have up to four different signatures if you want.
Thank you for the elephant compliments. It seems to add a photo you need to import your photos into your photo albums under your account settings? Or, if you have a URL I guess you can add that way as well.
The elephant model (from Aventine Miniatures, by the way) comes with a small tree stump to help support the front end. Hopefully it will look more like a tree stump and less like a vertically challenged rodent once complete.