I am getting a error CS0246:

error CS0246: The type or namespace name ‘ParticleRenderer’ could not be found (are you missing a using directive or an assembly reference?)

The Legacy Particle System was removed in Unity 2018.3, and script access was removed in 2018.1, see https://forum.unity.com/threads/legacy-particle-system-updater.510879/ for details about upgrading.