Giving orders to warships to fire upon the hex map is very similar as giving orders to air support, so only the differences shall be mentioned here.
One difference between warships and aircraft is that aircraft can have any hex on the hex map as their target hex, whereas warships can only fire upon those hexes that the scenario designer has allowed a person to fire upon. The way to tell if you can fire on a hex or not is to observe the cursor as it moves over the hex map: if it is a bulleyes cursor then you can fire on that hex, whereas if it is the standard arrow cursor then you can't fire upon a hex.
There are 3 warships that can be used like standard artillery barage, and these are Battleships, Cruisers and Destroyers. Bad weather can stop warships from being available. All warships are otherwise available, except for Destroyers which are not available during night turns.
If we look at the following image of the Naval Support toolbar we can see just how similar it is to the Air Support Toolbar:
As with the Air Support toolbar, there is one column for each weapon type. At the top of each column is a yellow title describing the weapon type, to the right of which are the up and down scroll arrows that one can use to page through the available weapons. In each column, each weapon has a number, some selectable text in a blue rectangle and some numbers in a round bracket.
The above image is from a daylight turn, the toolbar changes into something like the following image for a night-time turn:
Notice how there is now very little information for the Destroyers.
The second difference between Naval Support and Air Support is shown in the following image of the Naval Support toolbar, which we get in the planning stage after we having given the first of each warship an order to fire in the previous planning phase:
Notice that for our Battleship we now have (7/8) instead of (8/8), and that for the Cruiser we have (5/6) instead of (6/6), and that for the Destroyer we have (3/4) instead of (4/4).
What this means, in the case of the Battleship, is that out of a total of 8 possible fire missions that I have used up one (I can only set one barrage command per warship per planning turn) leaving 7 possible fire missions. Notice that this means that though I have used up one fire mission that I can still give orders to the Battleship without having to wait for it to re-arm. But if I keep giving fire mission orders to my warships they will steadily use up their possible fire missions. In the following image you can see what the Naval Support toolbar looks like immediately after I use up the last fire mission order for the first warship of each type during an execution phase:
Notice that we see something similar to the aircraft when they had to re-arm, only this time the re-arming delays are much longer. Since there are 6 turns per day, this means that it takes a Destroyer 2 whole days to re-arm, a Cruiser 3 whole days to re-arm, and a Battleship 4 whole days to re-arm.