Junior players coming into the AFL can pretty much all play footy. They are also better than their fellow juniors, so they do it easily in U18, etc. First thing they need to learn upon joining an AFL club is that strength is a huge part of senior league footy. Coupled to strength is defence. So, on entering the AFL the players should be taught defensive skills, tackling, defensive running, how to give and take hits and generally how to bulk up.
Once a group of players become seasoned adult footballers, they are then taught attacking strategies and tactics.
Currently the Dees are in my first paragraph, and probably several line breaks away from my second paragraph.