Ohh! Sorry I don't use the itchi.io installer, you should just download the zip file and extract it if you can.
There is a 'Download' section on the game page, click on it, go through everything and it should start to download a zip file.
When you are done downloading, extract the zipfile by using 7zip or winrar ( you can extract it by right clicking on it and click on extract )
It should be all, tell me if you need more instruction :)