This might help: How can i assign a footprint to a symbol?
Maybe this as well: What is the difference between footprints and symbols?
And this: Creating a new footprint library
And this: How can i install a specific version of the footprint library?
And for the symbol side of things (assuming you are running Kicad version 4.0.x): There should be a library called relay or relays or something similar. But it might not be added by default. Here an old topic that explains how to add the pre installed official libs either to only the current project or to every new project. Where are the momentary bush-button switches located?
If you run a current development build then the symbol libs handle similar to the footprint lib. (There is a lib manager that is similar to the footprint library manager.)
And a good tutorial for kicad beginners made by the guy who brought us this forum: https://contextualelectronics.com/courses/getting-to-blinky/