You first need to design in BBS code, which is what this forum uses for signature code effects, colors, etc.
For the record, it's BBCode (not BBS code) 
Oh man, SFR10, thank you so much for correcting me! Obviously, you're right it's BBCode. I hate giving incorrect information and I just forgot the correct name. It's great when we all keep each other in check like this, it keeps each of us learning!
I found another tutorial on how to write designs with BBCode, check it out: https://forums.enmasse.com/ava/discussion/303/how-to-write-a-guide-bbcode-tutorial