The every-day stock standard stuff is done with a series of fixtures.
They all have the same overlay. The distance from the bottom of the box is always the same for top drawers, so that is one fixture. Bottom drawer has one too, since it is different. If there are any in between, they are all the same, so that's a third. Those 3 fixtures are attached to one of the benches, in the assembly area. The front is placed in first, face down. The box sits on top of it, against the stops, and it gets screwed through pre-drilled holes. The holes are done during the CNC process, slightly over-sized, so slight adjustments can be made.
Most of the is 100% useless for home-shop hobbyists though [unsure]
For occasional situations it can be done by clamping the fronts in place. One at a time, starting from the bottom, install only that box. Clamp the front in place (front to back) reach inside and screw through the pre-drilled holes. This can be a little difficult in small cabinets.
Then install the next one up and repeat. A series of spacers can help, when stacking the fronts up.
It sounds harder than it is.