MQTT Sensor : how to define last_reset_value_template

I’m very new to MQTT and frankly almost all of this has gone entirely over my head…

I’m installing a Shelly EM tomorrow and was hoping to use it with MQTT (this was my plan before 2021.8 so it’s a really well timed update for me)!

Not a damn clue how to set it all up… why are there two sensors and more importantly are they both template sensors or what? I get the MQTT sensor but what the heck is the bit that Taras named ZP Import?