How do I obtain a medical marijuana card in California?

For some background, I am a resident in the Sacramento area (so if anyone knows of a doctor that can refer me for a card, that'd be nice) and I am 18.

Please don't refrain from mentioning anything like retrieving medical records or needing any sort of prescription prior to a reference to medical marijuana.

: http://alcoholdrugstreatment.info/how-do-i-obtain-a-medical-marijuana-card-in-california