Sounds like the Wwise Unity Integration doesn't initialize properly for you. Have you tried closing WAG -> delete the library folder -> then open WAG again? Otherwise maybe try to reinstall the integration, or even faster, just re-download WAG.
In the Wwise Unity Integration 2019, the toolbar has been replaced by buttons in the inspector, so you could also download WAG 2019.1 and use the new interface once the documentation refers to it. In short, the only difference is that the buttons have been moved and the points are now represented by child game objects to the Large Mode's game object.