Hello David,
You need a Unity project already created. After that, here is the process :
1- Launch : Wwise Launcher
2- In the Wwise tab, click "Launch Wwise (xx-bit)" (or click install New Version if not already done)
3- Create and save your Wwise project
4- Go back to Wwise Launcher and go to Unity Tab
5- Next to "Recent Unity Projects", click and select "Browse for project" from menu. Then selectect your Unity project
6- You should now see your Unity Project in the Wwise Launcher, under the Unity tab. Click "Integrate...." Make sure you have an internet connexion.
7- Locate your Wwise project and Unity installation files when asked.
8- Wait and it’s done :)
Hope this helps !