Your question suggests that you are looking for left and right buttons… But there is only one button: “Ok” which is equivalent to a traditional “left click”.

If you want to do something like a “right” click on an Android device, you may try a “long press” on the “Ok” button.
Unfortunately, there is nowhere on my NVidia where I can test such a right click ton confirm that it’s working… My NVidia is a console designed to be used with gamepads (so without “right clicks”).

I can only confirm that it’s working both as a keyboard and a mouse. Now, I have to say that I was already using previously a Rii Mini Keyboard, 2.4G. And to be able to use that one, I did configure my NVidia Shield TV to use the “External Keyboard Helper Pro” (available on the Play Store) instead of the AOSP (Keyboarb Android). That’s maybe the one doing the trick ?! (https://play.google.com/store/apps/details?id=com.apedroid.hwkeyboardhelper). Next to this, I didn’t do anything else than plugging the usb receiver and for sure switching one the rii i25 😉