Need wiring diagram for 320amp meter base wired to 2 200 amp breaker panels thanks

There are only three wires to deal with, 2 live hots, and one neutral. Feed the line side of the meter with all three, and the load will feed both panels.

The grounding is different depending on the location of the Main Breakers, either at the meter, or in the panels. This is not complicated but need to be aware of to get the grounding done correctly.

I am sorry, but if you have to ask for a wiring diagram for something as simple as this, there are many more questions you are not aware of, and more help is needed.

To answer how the grounding is to be done, best you explain the arrangement of this equipment, or provide a sketch.