LM210 part. +v and -v

Selected this part from the library. +V and -V are hidden pins. I’d like to use +5V and -5V for this device. I’m trying to figure out how to use power pins to connect up to this device leaving the pins hidden on the schematic. Help talks about using power flags and power pins. Can’t seem to make the connection; Help.

You could connect the hidden pins by using the button “show invisible pins”.
(I highlighted this button in red in the screenshot.)

But in my opinion your best option would be to create your on symbol based on the kicad official symbol without invisible pins.
It is a bit of work but in the long run it will be worth it.