I'm just confused about relays. For example, say for something like this https://uk.rs-online.com/web/p/latching-relays/0515571/ It says coil voltage is rated for 12VDC and switching current of 5A. Does that mean that to close the relay (turn power on), I have to apply 12VDC across two of it's terminals and as soon as that 12VDC is gone, it turns off? Or does that mean, I have to apply 12VDC to turn it off?
Also, what does the switching current mean?