Not sure if everyone already has this new submission page, but in case anyone gets confused by it, this is how adding installable journal skins works now.
Hope it helps some of you.
If you have suggestions for tutorials or anything similar, leave your feedback at my forum (see my profile). Basically the steps are:
1. Create the code and images files. For more tutorials check my tutorial folder: [link]
2. Create the needed .txt file (see this is you need further help: [link] )
3. Add the .txt file first and the previer afterwards.
4. Submit and add the single images. Done!