Can someone explain exactly how "Set Blackboard Value as "

I am studying behavior trees for characters to have motions on their own. I can’t seem to find detailed documentation on "Set Blackboard Value as ". There is alot of use of it, but I know I’m missing something. Is it changing something in the blackboard to the value you give?? Or are you setting something to be the value that is on the blackboard? As you can probably see from the questions, I’m missing the context. Please don’t link to other pages with code, I don’t need to see it used, I just want to know exactly how it works and exactly what it does. Thanks!

Yes, you pass it a value and it writes that value into the blackboard, overwriting whatever was already stored at the specified key.