Crowd flow is decided by the layout
Not by stewarding on the day.
Where people go, how densely they pack, and where they stop moving are determined mostly by the physical arrangement: entry points, sightlines, the position of bars and toilets, the width of routes and where they narrow. Stewarding manages the consequences of the layout and cannot overcome it.
The dangerous configurations are well documented: routes that narrow in the direction of travel, opposing flows meeting in a confined space, a single attractive point drawing a crowd into an area with limited exit, and any location where people at the front cannot move but people behind continue to arrive.
The schedule interacts with all of it. Everything ending at once produces an egress surge; a headline act starting on time produces a rush toward the front. Staggering, and communicating clearly, spreads both.
This is specialist work. For anything at real scale, crowd modelling and a competent safety adviser are not optional extras, and the applicable legal requirements, licensing conditions and any duty to appoint qualified persons should be established for the specific jurisdiction and venue.
The other layout factor that is decided early and rarely revisited is where people wait. Queues form at entry, at bars, at toilets and at exits, and a plan that shows the facilities without showing the queue space they generate has omitted the thing that actually occupies the site.