Firstly, make sure you downloaded the PC version of the game. Secondly, you will need to right click and "extract here" or "extract (folder name)" and NOT the "extract files..." option. This option will get you nowhere, the game needs to be in it's own folder on the desktop, just chilling there.
From there, inside the folder should just be all the regular 'ol files that you can ignore, except for the .exe that should be titled "SolanaceaeAnotherTime" and have a little picture. That should then open the game.
Ren'py games don't need any install and just work out of the folder-- so if you're having any troubles beyond following this there's unfortunately not much I can do for you-- as I did not program the system I just made the game within the system. Google will be your next option if this stuff doesn't work.