If you go to your own profile by clicking on your screen name at either the top or the bottom of the page you're looking at now, you can scroll down and see the options for editing avatar and signature. The avatar is the one on the side and the signature is the one on the bottom.
Like was stated one post ago, click on "The betta house" on the top left, where it says "logged in as:" and "(Log Out)". Then, the rest of the above post works.
Another thing is my controls, also as stated above. This is located on the top right, to the far right of your name and "(Log Out)". After that, click "Edit Signature" to add text and/or pictures under your posts (or in the signature), and click "Edit Avatar Settings" to add a picture under your name (the avatar ).
where anything between the IMG blocks is the website it is from. You might need a picture host like photobucket.
But if you want a signature, click on My Controls, then click on Edit Signature. Coding is the same as when placing an image in your text area, what I have shown you above.