Storage rings are the principal sources of high brightness photon beams driving the majority of x-ray science experiments in the world today. Over the last two decades, there has been remarkable progress in developing these sources. Existing third-generation light sources continue to upgrade their capabilities, while new light sources storage rings are coming on line with ever-improved performances. Strong nonlinearity, significant collective effects, and the need for novel beam injection methods are the most demanding aspects in designing a low emittance storage ring. This webinar will address the challenging points of the Iranian Light Source Facility (ILSF) storage ring lattice design as a real example of a low emittance storage ring.