First of all, Voxengo software does not feature third-party ads nor malware nor unexpected bundling. The software is routinely checked for the absence of malware at VirusTotal. User account registration is not required.
In order to install this product you will need to download its corresponding setup file to the computer you are planning to use this product on (Internet connection is not required for the product to function).
For VST, VST3, AAX plug-ins on Windows:
You should execute the downloaded setup file, select plug-in types you would like to install, and for VST plug-ins specify the "VstPlugins" folder location - the one which is connected with the audio application you are using and where this application expects VST plug-ins to reside (the "Voxengo" sub-folder will be created there). VST3 plug-ins are always installed into the standard "Common Files/VST3" folder. AAX plug-ins are always installed into the standard "Common Files/Avid/Audio/Plug-Ins" folder.
(the installed Voxengo plug-in DLL files can be moved around freely)
For AudioUnit, VST, VST3 plug-ins on Mac OS:
Open the DMG disk image you have downloaded, and drag & drop the "component" ("vst", "vst3") file into the corresponding plug-in folder located in the "/Library/Audio/Plug-Ins/" folder on the hard-disk (the "component" file should go to the "Components/" sub-folder while the "vst" or "vst3" file should go to the "VST/" or "VST3/" sub-folder). Direct links to these folders are present in the DMG files - they should be double-clicked to open.
Note that you need to install the "component" file (AudioUnit/AU plug-in) if you are using Logic Pro, GarageBand, or other AudioUnit-compatible audio applications.
(Please note that the "component" file is distributed in the "AU, AAX" DMG file, while the VST file is distributed in the "VST, VST3" DMG file.)
For AAX plug-ins on Mac OS:
AAX plug-in can be installed in a similar manner: the "aaxplugin" file resides in the "ProTools AAX" folder of the opened DMG disk image. This file should be manually copied into the "Plug-Ins" folder on the hard-disk, for which a direct link is available.
After this has been done you should order your audio application to rescan plug-ins, or if that option is unavailable you should re-start that application. Note that plug-ins cannot work without an audio application that hosts/loads them.