You can install the Wwise Integration package using the Audiokinetic Launcher. Refer to Integrating Wwise into a Unity Project for details.

Warning: Before you begin: Back up your Unity project. You can either rely on your source control system or use the Audiokinetic Launcher. To back up your project through the Launcher, ensure that Install files into a copy of the Unity project directory, then apply changes if successful is selected on the project integration page. Before you install the Wwise integration, you need to make sure your Unity project is in a state where it can compile successfully without any errors. (Warnings are OK.) If the Unity project is under source control, make sure to check out the whole Unity project folder before starting to integrate. Otherwise, the integration will fail because it won't be able to modify the files.

Unity Integration Extensions

Users hooks, in the form of partial methods, have been added to allow users to extend the auto-registration of game objects or remove this functionality all together. The default extensions are recommended, however, you can choose to exclude them while Integrating Wwise into a Unity Project.