Thanks for updating the thread.
I have recorded a screencast that you can watch to manually upload the theme. Please take a look and let us know how it goes. https://cloudup.com/cKt3uQdskko
Once you upload the theme, open wp-admin section and click on X. Doing so will automatically install Cornerstone plugin.
Next, enter the purchase key to validate.
Please let us know how it goes. In case you are facing issues with validation, please upload the theme files using software like Filezilla and let us know.
To get started with Filezilla, please take a look at following resource.
You can download Filezilla from following resource.