to post a signature go to
on the top of the website click >>> Profile
than on the left side you click on >>> Forum Profile
than you see a small white chat box with
Signature:
Signatures are displayed at the bottom of each post or personal message. BBCode and smileys may be used in your signature.
if you have a image with a link than type this in the chatbox
[img]http://www.----image link here-------.com]/img]
To make a own image you must make 1 with for example paint or Adobe Photoshop CC 2014 and than upload it to a website that can make a link for it.
i myself use the website
http://postimg.org and than use the steps above.