Okay. Assuming you are completely incompetent(not that you are, but sometimes people make silly mistakes) here is how to change your armatar in four simple steps.
Step 1: Look in the upper right corner. You should see your username(Angelofdeathandlight) and beneath it two links that say "Control Panel" and "Logout". Click the Control Panel one. Step 2: You should see a large heading that says "Edit Profile". Underneath it there are several text boxes for you to type in. Ignore those, pay them no mind. In the upper right of the "Edit Profile" thing, you should see four links: "Profile", "Armatars", "Games", and "Friends". Click on "Armatars". Step 3: You should see several small pictures with clicky bubbles underneath them. These small pictures are called "Armatars" and these are the pictures that represent you and will be next to your name(Armor + Avatar). Click the bubble beneath the one that you want. By gaining AP, you will unlock more armatars. 4. Scroll down to the bottom of the page and click "Update Armatar". And now you're done!
On your top right corner under your username,it should say control panel,click on it and it will take you to where you can edit your profile and again on the top right corner click on ''armatars''.It will show a page with armatars(armorgames avatars).Click on the bubble underneath the one you want.After your done choosing,scroll all the way down and click ''update armatar''.And now you should have it.