How to add an instruction to a square

How to say a command to add a block, the player can left or right, click to execute

I’m assuming your asking if there is a plug-in that allows you to add commands to arbitrary blocks?

Yes, I need such a plugin

I’m unsure if there are any plugins like that currently in existence. It’s not a terribly difficult plugin to make thought, so I wouldn’t be surprised if there is. Have you checked Ore?

I have seen the ore, but it is not, so I came here to ask about

Something like this?

What does this mean?