Instructions for applying to medical school can be found online in the 89-page AMCAS instruction manual.
Click Here to Download the Manual
That is not a typo! Eight to nine pages. It is never too early to download the manual, and begin to understand the process.
AMCAS is the American Medical College Application Service, a part of AAMC, the American Association of Medical Colleges. AMCAS is a centralized application process that allows you to apply to all medical schools (except for those in the state of Texas, which has its own application processing service.)