# Trajectory following using LQR - Setting horizon time and intermediate points

I was going through UC Berkeley's CS287 - Advanced Robotics course. In particular - Optimal Control for Linear Dynamical Systems and Quadratic Cost (“LQR”) by Pieter Abbeel (Slide 10).

Let us say we use LQR to go from point A to point B. The motion planner will probably output a trajectory, which we will follow using LQR. In the finite horizon discrete time case, how do we set the value of total time horizon $T$, and the value of each time step $\delta t$, and the waypoints $x^*_t$ to follow?