and save the result as either a compressed or decompressed folder.
-> file or folder ?
Folder. The tool loads in the 00slot00 folder in the exported save, and saves a folder.
The original post should mention that you need some sort of way to run homebrew, whether it be gateway or another method.
There's very little in the original post that suggests it.
Actually, I think it is perfectly clear, given that I mention you need decrypted saves in folder format.