Corona has its own menu that lets you add lights, open the VFB, etc. as shown below:
You can add these commands directly onto your toolbar using the regular Cinema 4D customization methods. Use Window > Customization > Customize Commands:
In the dialog, search for Corona to display the Corona commands, and then simply drag the commands to a menu, just as you would when customizing the C4D interface normally:
And be sure to save your layout once done!