Obviously they would need to buy some and store it in tanks. The United States does it by storing petroleum in voids they dissolved out of salt domes. 713.5 million barrels (42 gallons per barrel = about 30 billion gallons just sitting and waiting to be refined into gasoline, diesel, kerosene, asphalt, whatever is needed)

If Florida did it, they/we would need to buy the fuel already refined, decide how much to spend, how to pay for it, what mixture to store (maybe three months’ worth of current demand, just as an opening thought).

Very likely there is already unused capacity around the state so it could be handy for distribution, just buy a few billion dollars’ worth, keep it in tanks and sell it back every month or so, buying more with the proceeds.

AND
” why does a state, in the richest country in the world, the third largest (state), why don’t we have a significant gas reserve in the central part of the state”

Probably because we don’t want to mix government with commerce or tie up wealth for something useful some day in the future when we have current needs demanding attention. Imagine spending much on this reserve and then everybody switching over to electric vehicles, not needing fuel. Someone would be demanding to know why we wasted the money.

David for nuclear cars