cheers
@R-Rated
@Mr. G to edit your signature click on your name top right of the screen, then click on signature. You'll then be able to cut and paste your youtube channel url into it and save it, or you could click on signature and then type "My YouTube Channel: CLICKY" and then highlight the word "CLICKY" and then click on the add link button, that will open a pop up window where you can paste in your YouTube channel's url and click save, it will then look sort of like mine, you can use a different word than "CLICKY" but you have to highlight it before clicking on the add link button.
Hope that helps mate