Playing the Power of Three Mystery, on Blue Sun. It shows me "You are at step 22 of 24 steps", "You are waiting for time to pass", and "No clues why".

I have researched both Dark Spectrometry and SHEPID. Based on the wiki, I am supposed to either store cubes, build decorations or destroy cubes, but I have no damn idea how many, if there're any additional conditions (such as proximity to buildings) or how many days to wait after a condition is satisfied. I have stored >12 depots, built about 7 large monuments, to no avail. I did not get any event on cubes pulsing light even though some walkthroughs have it.

Sherlock simply shows me the above.

This is infuriating.

Yeah about that. I didnt program in the ability to actually show you next steps so its not too cheaty.
I'd give you the answer to the next step but with that mystery, the time between events is random up to a few sols and then it checks a condition of number of cubes and loops again if under it.
If the cubes are less than 10800 that "time Wait" condition will remain.

What is happening is (Spoiler)...

The cubes are being collected to build a massive structure.
If you are destroying them or building with them, then you are just delaying the next step.
However, if you dont destroy a few they may destroy something in your colony.
So just dont go too overboard, and building things like statues with them is pointless, that is pure delay.