On this page: the remaining D5100 settings that you can use to customise the behaviour of your D5100 and that are not already mentioned in other chapters.
It is common for cameras to beep when the autofocus succeeds in focusing. And there are many who find this annoying... if you are one of them, turn it off. In the custom settings menu . A running self-timer makes the same sounds, you can only switch both on and off together.
Alternatively, you can set a slightly higher or lower beep.
The custom settings menu defines the time after which the monitor switches off, separately for
Set a longer time here if you are bothered by the monitor switching off too early.
In Nikon's default settings, the D5100 will not release if no memory card is inserted. You could change that in the custom setting menu . Photo shops do this to demonstrate the cameras, I can't think of any other sensible reason.