How do microstrips actually represent lumped components?
How do microstrips actually repersent lumped components?

It is actually the other way round!

A microstrip is a distributed component. It has a length and that length has (continous) capacitance and inductance all over its length/width/height

This is difficult to do calculations on as the number of elements (inducators, capacitors, resistors) is basically infinite.

To simplify things a lumped components model can be used, which simplifies the infinite number of components to a finite number.