Hi! I'll do my best to explain!
> Click the green "Download Now" button
> Click "No thanks, just take me to the downloads"
> There's a list of versions of the game. If you're on a computer running Windows, click the "Download" button next to "AsagaoAcademy1.0c-win.zip." If you're on a Mac, click the button next to "AsagaoAcademy1.0c-mac.zip." If you're using Linux, select the one next to "AsagaoAcademy1.0c-linux.tar.bz."
> The game downloads as a zipped folder that you'll need to unzip. If you're using a Windows computer, I recommend the program WinRAR. It's free. Right click on the zipped folder and "Extract Files". Set the destination to anywhere EXCEPT your Program Files folder and extract. If you're on a Mac, I think you can double click the zipped folder to unzip it? I have a PC, so I'm not sure... I wont be able to help you unzip the game with Linux as I've never used it.
> Open the unzipped folder and inside is a blue pixel flower icon called Asagao Academy. Double click that to launch the game!