After Basic, many sailors go to A-school where they learn the initial starter information to function in their rating. The rest, including a good many people who have no idea what they want to do, go to their first duty station. Later they can complete "3 & 2" correspondence course for the rating they want to go into.
Navy correspondence courses are open to anyone. I checked, and find out I completed the "3 & 2" courses for 19 different ratings. This was mostly self-defense because of the large number of different ratings I had work for me over the years.
WWG1WGA
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)
MatQ