Absolutely correct--- the parent must either be, well, a PARENT or a teacher (perhaps both).
Choose an EXTREMELY simple, straightforward physical task, break that task up into absolutely fundamental chucks, assign a [child-unit]* to each chunk, execute.
*[child-unit]: Depending on how many kids you have and how you want to structure things, assign your kids to work as either individuals or small groups. I'll return to this in a bit...
For 2nd grade, I'd suggest opening up by having the children consider single-task robots. They'll dig that. A bot can perform ONE physical movement.
The task is to move a box from Table A to Table B.
Break the movements into chucks like this:
a: Grab box, elevate from table height to chest height
b: Accept box at chest height and pivot left/right from a stationary position
c: Accept box at chest height and move back and forth on a linear path from Table A to Table B
d: Accept box at chest height and pivot left/right from a stationary position
e: Accept box at chest height, lower to table height and release
Following this model, you need three kinds of kid-robots: Lift/Lower, swivel cargo, transport cargo.
If you explain and demonstrate each chunk, they'll get it.
For 4th grade, do the same except lead them in a discussion to discover that the 5 chunks only require three discrete actions, and have them outline the order on the chalkboard. In essence, they'll be writing code.
Good luck, consult the classroom teacher for assistance with the lesson plan, and above all HAVE FUN !!