I watched Tony's tutorial on the new D850 and realised that I don't know how to control my D750.
Based on his review of the D850's controls I learned this:
1. In LiveView you can show the exposure preview meter.
Turn LiveView on.
Press the i button (botton LHS)
Use up-down on the pad to display or select various shortcuts, but pick exp. OFF (if its off) and use the L-R in the pad to turn it to exp.ON. Thew scale appears on the RHS of the screen.
2. Histogram or other information on the screen.
In LiveView, press the "Info" button (above the pad) to get a list of features that will display on the scree.
Repeatedly press it to cycle through the choices. I set my to show the histogram.
I find it handy for landscapes and that sort of thing.