I have created one more video explaining what to do best do giving certain team setups:
https://youtu.be/BGi2dZmTGA0
Basically there are three variations:
A. 3 Battleships + 2 Cruisers + 2 Destroyers (Very common)
Split the fleet and cover left and right flank.
Weaker fleet tries to hold and delay enemy advancement.
Stronger fleet tries to take both flags on it's side and assist weaker fleet.