check my journal and others…
few links
https://elitetrack.com/forums/viewthread/8424/
https://elitetrack.com/forums/viewthread/8331/
https://www.athletesacceleration.com/blog/2009/08/24/steal-my-400m-program-week-1/
in making a plan i suggest you identify your strenght and weaknesses are you a 800/400 or 200/400