How did they learn to do all of the steps to dive the boat in the right order?

The same way that musicians get to Carnegie Hall – practice, practice, practice. Experienced crewmen had probably submerged submarines hundreds of times. They trained the new submariners in how to do their tasks so all of these steps were done quickly and efficiently.

“It was only when they did this thing as a sort of second nature and in teamwork with everybody else that they can be called a first-class crew. Such a routine as that was not learned overnight nor out of books.” (“Battle Below” by Robert J. Casey, Bobbs-Merrill Company; New York; 1945.)