How to disable Peek/Heads up notifications on LG G5 with Android N
are you looking just to shut off the notifications?

If so:
from the Home page -> Pull down from the top and click on the Sprocket (or Settings) -> If you have the Grid View click on the Sounds&amp;Notification -> Click on Apps -> Scroll down and click on Settings 

From here, you can control you want the Peek, but making silent, or click on the Lock Screen and Hide all notifications.

I hope this helps.