Well, to be truthful, most of it is inferred through a composite of studies in archery, so there's not a "manual" that tells you exactly what to do
per se, but there are accounts through a variety of literature that details at which range the archers started shooting with their eyes "OFF THE TARGET" -- which means they were aiming at a distance which requires the bow to be raised above above the level at where you can track the target with your eyes.
For example, "The English Bowman..." (T. Roberts, 1801) details on the elevation of the bow during shooting, and clearly mentions that while discussing elevation. And, Roberts puts the distance where direct shooting not requiring any elevation at somewhere around 30 yards, and with stronger bows (including war bows) the distance could be somewhat further off.
(Read from page-99)
So from this it can be inferred that the archers would start shooting at around 150~200 yards, which required elevation of the bow much too high to keep eyes on the target. Logically, this mode of shooting would require coordinated shots to maximize volume of fire to be effective, which means they would be firing in controlled volleys. Some other sources mention on average 8~9 volleys are fired from the very start of archery fire with enemies in range. To be very clear, if you were shooting-at-will individually, any archer can fire a LOT more than 8~9 shots when a mass of men are approaching from around 200 yards out.
Then, around within 30 yards or higher (which brings in to the 30~60 range we can see in-game) the archers were able to start shooting directly, with each of the archers able to set their eyes on tatget. (termed, "point-blank" elevation in the book). At this "point-blank" range, again, you don't need controlled fire anymore. So we can logically presume that would be the point where the archers switched shooting method, in most cases.
And many accounts detail that such a volley fire did happen. For example, "The British Archer..." (T, Hastings, 1831) describes numerous such accounts from the 100 Years War, so we DO know archers were assigned commanders that ordered firing in volleys.
(Search for keyword: "vollies")
Unless we want to presume the English archers practiced some very distinct and specific methods that only apply to themselves, I think it's logical to assume most archer units around the world would probably have practiced similar tactics.