How would I volenteer

How i would volenteer my services to my country is i would go into the air force and help with whatever they needed. I would do anything they needed my help with. i have an older brother who is in the Marines and he inspires me to help my contry. Im not one for fighting but were i live is very importent to me, and my friends and family mean the world to me and id do anything for them as well even if it means risking my life and going to into battel to save them. Thats what i would do to surve my country and what I would be in to surve it