Passion,
Like what kucinghitam said, CV and cover letter are basic job application documents. Furthermore, CV and cover letter offer you the opportunity to 'market' yourself in aspects that are missing in the application form. A medical report is not required.
To apply, start preparing an excellent cover letter, CV, application form and with lots of luck, subsequent instructions (eg visual acuity test) will be given when you are notified for the 1st interview. Three years is alot of time to build up your resume and aviation knowledge. Make good use of that time.
Cheers.
9V