Similar thing is in hockey. The rules of hockey will not tell you how to win. The same way language grammar will not and can not tell you how to write a winning novel or screenplay. The rules of hockey are hockey axioms, and you use them to create instances of the game, within the rules framework. Each game is a set of theorem obtained from the initial hockey axioms, and proved by the way of arbitrary not interfering with the game.
In Physics, differential equations can not tell you how to construct a new machine or make an invention. Why? Because differential and integral equations are waiting for YOU to tell them their initial and boundary conditions, i.e. STARTING CONDITIONS, they are waiting for you to tell them what and when to calculate, in the form of integrand, integral limits, initial and boundary conditions.