Polymod Tutorial
Create a folder in the polymods folder and rename it to whatever you want.
Doing this manually is not a problem, but it would be faster if you cnp'd the Template in the polymods folder.
The information for the mod is stored in two files. Those two files are _polymod_icon.png and _polymod_meta.json.
In _polymod_meta.json, you can define the mod name, the name of the author, etc.
Now, about _polymod_icon.png, it's just a simple .png icon for the mod. Just keep in mind that whatever image it is, it will always be squishes into a 150 by 150 resolution. So a 1:1 aspect ratio is recommended for your image.
So now, what do you after all that you may ask? I don't know. But, I'll let you know when this is improved and you can go further in this process.