Go to the "User CP" page. Click on it. Next, look for the area that says "Your Control Panel". About the fifth section down, you should see where it says "Setting Options". Under this header you should see "Edit Avatar, Edit Signature, etc....". Click on Edit signature, and you should be able to add whatever you want.
As for the periods & #'s... it just shows how many male/female/babies/eggs you have. The order is as follows:
# of males . # of females . # of babies . # of eggs ready to hatch.
Ex. If you have 1 male leopard gecko, 2 females, 3 babies, and 4 eggs ready to be hatched, you'd type out as...
If you had 1 male dog, 1 female, and no babies, you'd type it out:
If you have 4 male cornsnakes, 2 female cornsnakes, no babies, and 3 eggs, you'd type:
18.104.22.168 (if you have no eggs, it would be)
I hope that makes sense. If not, let me know, and I'll try to explain it a little better.