To generate production files you need to export a .zip folder with all nessesary files. To do that (with KiCad) please follow the tutorial from JLCPCB. You can also use dedicated KiCad manufacturing plugin.

After going to JLCPCB press Instant Quote button and upload your file.

After the board preview is shown, you have multiple optionsto adjust. Every option here i very clearly marked and described (when you hover over the question mark). 

JLCPCB is also a sponsor of this whole project (not only this PCB, but all the PCBs in the car!). JLCPCB (Shenzhen JLC Electronics Co., Ltd.), is the largest PCB prototype enterprise in China and a high-tech manufacturer specializing in quick PCB prototype and small-batch PCB production. You can order a minimum of 5 PCBs for just $2 (2 layers), just enough to have a few test/spare ones.