You need to upload the smilies as attachments in a post to your forum first....in this thread...
http://support.forumgogo.com/thread-14-1-2.html
Then go into your Admin control Panel, click on posts across the top, then edit smilies on the left hand side.
Now, you can either leave the ones that are there, and add more. Or, delete the existing ones and add them all a fresh.
Now, you need to go bk to the post where you uploaded the new smilies....right click on the image, and go down to properties...then highlight all of the URL, this is what you paste into "smilies filename" then you can add a "smilies code" of your choice....when you have added all that you want to, click on submit at the bottom........Hope this helps m8..
Bibbs