Pete
That's why I think a few hours of instruction on the basic principles of field fortification would be a good idea in schools for junior officers.
Not something you can learn in a few hours, but training and education in this subject is essential and always has been.
How long does it take to train a Mortar Platoon Commander? Well learning how to site and construct FOBs/COPs takes way more skill than commanding a mortar platoon. Siting and construction is really something that should include formation level staffs.