I don’t mean the actual rules of passing it, I mean what organization, activities and funding are necessary to do so.
The last one passed was in 1992 and it was just about congressional pay. Last one before that was 1971. Is there some kind of play book? It seems to happen so infrequently that it would be hard to study and conditions would vary enough that the last effort wouldn’t be useful as a model.
(“The amendment process is very difficult and time consuming: A proposed amendment must be passed by two-thirds of both houses of Congress, then ratified by the legislatures of three-fourths of the states.” Link)
You said it, the details are going to vary too much between specific attempts to give a single answer.
This is one of those rare times that reddit would have been perfect because of r/askhistorians. You could at lest have probably gotten partial answers for specific amendments and cobble together a guesstimate on what a modern effort would take.
But just from a bit of memory based on very old classes, you’d be looking at years of sustained groundwork to build support, and that’s going to be millions to billions of dollars spent in propaganda (which isn’t an inherently negative word when used broadly), and awareness raising, plus man hours beyond my ability to guess.
I know that even that last one took a lot of work to get started.