Elementary TPRS is TPRS embedded within a classroom management framework suitable for the age group. That’s it.
This assumes the teacher knows and can provide real TPRS to begin with — by which I don’t necessarily mean “the teacher can keep a storyasking session going for 30 minutes”, but “the teacher can provide input that is truly comprehended, truly personalized, and truly repetitive”, reliably and consistently.
Elementary TPRS is maybe 25% TPRS (that’s what I call CPR: comprehended, personalized, repetitive input) plus 75% age-appropriate activities using the same language that are hopefully input-oriented but not necessarily always completely input-oriented (in practicality and reality). The main issues are addressing learners who are pre-literate in L1 to begin with (slight modification in establishing meaning, no big deal) and making sure that input (most importantly) and the supporting activities are delivered in chunks of an appropriate size for the attention span and cognitive development of the learners. After 6th grade-ish that becomes more the same for all ages (insofar as anything does when we’re dealing with real people. But it’s easier to generalize and say middle/high school or even adult ed works “this way” than it is to say all elementary pre-K to 6 works one way).
The CPR needs to be real, rich input as well. Too much FLES is limited in outcome because it’s limited in input. If you only teach lists of words, you shouldn’t be surprised that all your kids can do at the end of five years is recite lists of words. On the other hand, it’s so easy to provide them with solid, basic language structures, and repeat them enough that they “stick” and start to be output, instead of simply going for the easy thematic wordlist plan. And the outcomes are so much different.
Getting the right mix of kinesthetics/movement, listening time, making sure everyone gets a turn for the lower ages, concreteness versus abstraction, managing behavior — those are not really TPRS per se. Those are classroom management or knowing how to teach that age group. Any good teacher of the age group will do these. Only a skilled TPRS teacher will provide the CPR input while doing those other things, and that’s what makes the difference between a FLES program that delivers the too-common outcome of kids who can chant their numbers, days of the week, months, colors, and sing a couple of songs, and kids who can speak the target language in a basic way.