Once the plugin is installed and authorized, open your DAW. Most modern DAWs (like Cubase, Ableton Live, REAPER, FL Studio) have a VST Plug-in Manager. You will need to either manually scan for new plugins or restart the DAW. The DAW will scan the VST3 folder, detect the Ozone 5 plugin files (which have a .vst3 file extension on Windows), and link them to your plugin list.
If the problem persists, uninstall Ozone 5 completely, then reinstall. Ensure that during installation, you select the correct plugin formats (VST2 and/or VST3) and bit versions for your system. vst plugin izotope ozone 5 vst3 link