Just like always simply drag'n'drop it to your addons folder.
Content should be downloaded automatically from workshop.
Config placement is at hidcams/sh_config.lua
There is an important thing to know - frame limit will make resource load be non significant, however sometimes your flashlight's flickering may occur because of this. If you disable frame limit, there will be no such things, but you may experience some load on a huge map or with a big amount of cameras.