RTC Jetson Nano

Hi

Looked at the Carrier Board Schematics and found we can add a coin cell to J45 to retain the RTC time,
and the recommended coin cell is CR1225

Now needed to know few things
1-what are the steps required to setup the internal RTC software side.
2-In terms of hardware we need to only connect the holder and and a coin, right and why the 3 terminal?
3-Will a Non rechargeable coin cell work or we need rechargeable one ?

Thanks

I use the CR1220 because those were the holders I had on hand.

1: Nothing. It’s enabled by default.
2: I didn’t do anything with terminals. Just soldered the holder’s 2 ears to the board.
3: Non-rechargeable’s work fine.