Those are for windows. The download pages says
Win32 compatible system with SSE2 (or higher) instruction set support
So they don’t work on Linux, nor macOS. There are some tools to run Windows plugins on Linux, but if you need to use Windows plugins, you’re usually better off using Windows.
Edit: You can check Menu > Window > Log to get information about the plugin scan information. Likely the plugin(s) are blacklisted because they cannot be loaded, or they’re ignored if they’re .dll files.
At this point in time there are not yet a lot of Linux VST3 plugins. Some commercial vendors that already do include https://www.auburnsounds.com/, https://u-he.com/
Most free/libre plugins are released as LV2, you can get those via synaptic on Ubuntu
(there is a meta-package