This is not a job for beginners you will have thousands of dollars in paint and materials for a job done correctly You also will need a pressure fed paint application so you can mix and spray several gallons of paint. Enclosed building what type of ventallation will you use? The devil is in the details and doing this alone you will have weeks of prep work, masking,sanding and primeing. Then everything has to be perfectly clean dry and tacked I was in the auto body biz for years and would not tackle it.