There is nothing to appologize for. I had my first sig made for like a month and a half before I actually knew how to use it.
Okay this may seem complex, but once you do it, it'll be easy as cake.
1. Save the image to your computer.
2. Go to this website
http://imageshack.us/
3. Upload the image at this website
4. Copy the code you need (I always use the Direct Link)
5. Go to settings in Zelda Dungeon. It's at the top right.
6. Go to change signature on the left side of the screen.
7. Click on the upload image button. It looks like a tree or something.
8. Paste the code you copied from image shack.
9. Save your changes.
Like I said it seems complicated but it is really easy.