Hi,
How did you install it ?
And if you installed it and the install was reported as successful, then you should find it in your Joomla plugins manager.
If you don't, then there is an issue with the user right on the folders/files or with the Joomla installer.
What you can try is to use the "discover" system of the Joomla installer system. There, you might find the plugin and going through the discovery system might allow you to finish the install. I've had that a few times on some Joomla websites where the install was reported as successful by the Joomla installer, but the plugin wasn't in the Joomla plugins manager and the discovery system helpd finish the install.