See Offence - Billy Donovan ballscreens.
After a made basket, everybody has a role (a numbered fast break). They don't really play out of a secondary break, they flow right into offence without stopping. 5 runs under the rim and posts up, 1 gives him a look. The wings get below the first marker, they don't want to load up the floor on the point guard, give him a lot of space. They want the floor to be open.
Running after missed shots, the assigned lanes on the numbered break go out the window, and they could start the break with 1 through 4, he doesn't care who brings the ball up the floor.
If two wing players are on the same side, they never cut across the floor, the first one gets pushed through.
The first post always runs to the rim, the second post trails.
If 5 rebounds a missed shot and first-post 4 is not a post-up guy, they want 5 to run into a pick and roll with 1, 4 replaces.
1 hits 4, who looks inside then passes and sprints into a ballscreen.
If X4 and X5 are in front and waiting, and 4 and 5 have no advantage to get to the rim, they run right into a double pick and roll after 1 hits 2 and goes away. 5 always rolls, 4 pops.
(Variation - double-screen for 1, see Fast breaks - Phoenix Suns drag screens, Spurs 2014).
If 5 is the first big and goes to post, 1 hits the wing and goes away, 4 can run right into a pick and roll.
Or 5 posts, 2 gives him a look, 2 throws it to 4, who looks at a high-low.
See Fast breaks - Florida 2006.