This is probably the best land renovation project in history. All you need to do is desalinate as you go, use plastic pvc piping, and have a renewable energy source to pump the water, and you create an arable land business where land that is at first of no value become land people who purchase- right out in the desert where it was unliveable previously.
The second consideration is that there are people in the world living in areas that have devastated by famine. These people don’t have fresh water to farm with, this is why they starve- they also have less money and social and infrastructure resources that city people take for granted.
Long term planning is an area in which they can improve during times when there is no famine. Often reaching out to others might happen when there is for example, the death of a baby due to famine. That would inspire people to seek help from sorrow. They might not have a plan to bring water in a way they never have. They would not consider using salt water because the land would be ungrowable for edible plants if the salt is not removed, but it can be removed.
So whether you use hho or solar energy or wind or wave power or even gasoline to fuel the pump, that pump can suck ocean water out of the sea out to the desert where land is not fine, but there is dirt.
There it will be distilled either by heat or normal evaporation, and either captured or not. The remaining salt will itself be accumulated in places where it can be removed and centralised for shipping to a trading center. Sea salt can be sold to cities for industrial and agricultural uses- it is tradeable. It can be used to prevent road slippage during snow storms, and is a standard food seasoner and preservative.
The pipes should be placed through the desert dirt like the veins in your arms. They must give the blood of the sea to the body of the land, so that the land will become flesh for you to eat. The animals will be happier that there is fresh water, and the plants will spring up new.