Take 2 picture (your icon HomeBrew).
icon1.png = size 24x24
icon2.png = size 48x48
Put icon1.png in the ctpk_24x24icon folder and run the icon.py file.
Put icon2.png in the ctpk_48x48icon folder and run the icon.py file.
Return to the root of the folder.
Open AppData.txt.
Change what is between quotes by what you want:
longtitle="Homebrew Game"
shortitle="My Game"
publisher="Asia81"
Save the txt, and run the _buildscript.py file.
A icon.bin file is generated, rename it [YourHomebrew].sdmh.