Add several values together

Configuration
1

I a bit stuck.
Having a 3 phase meter, wich are messuring power/energi on each phase - Shelly 3Em.
I want to get the total enegy from the 3 phases added together.
I can´t get figure that out - help would be welcome-

2

Use a template sensor, that sums the three dedicated sensor‘s state. See example on the min/max integration.

3

If you just want to add the three energies together then like this

sensor:
    total_energy:
      friendly_name: "Total Energy"
      unique_id: "Total Energy"
      unit_of_measurement: "Wh"
      value_template: >-
        {% set e1 = states('sensor.phase1') | float %}
        {% set e2 = states('sensor.phase2') | float %}
        {% set e3 = states('sensor.phase3') | float %}
        {{ states('sensor.total_energy') | float + (e1 + e2 + e3) }}  <---- this will create a rising total

I am assuming the shelly 3m is recording a consistent period energy? Power*time and records this ever x (min/sec) period. If not you might wish to look here: