You actually need to copy a folder deeper within the zip file to the root of your site. From either the dotnet35 or dotnet4 folder (depending on your installation), copy the contents of the wwwroot folder to the root of your site. Note that if you are using a database other than MSSQL you'll need to perform an additional prerequisite step to choose and copy the correct data layer DLL. Full instructions for the installations can be found on the System Requirements/Installation tab on the Event Calendar Pro and Form Wizard Pro store pages.
When you have everything done correctly, you'll see something like this in your setup:
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Configuring feature Form Wizard Pro by Source Tree Solutions - 00:00:06.9218307
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Configuring feature Event Calendar Pro by Source Tree Solutions - 00:00:07.5624516
...
Hope that helps,
Jamie