Place inventory Items In World

SikkJewFro

So, putting this as simply as I can, I want to be able to click an item from my inventory and have then be able to place it in the world, as in, Highlight the hotbar (1-0) and then whatever item is in that highlighted hotbar, allow the player to click somewhere on screen and place it down in the world. (Just like minecraft except 2d). Also, it seems like a simple process i'm just at stuck figuring out a few hunches that Im hoping someone else has a better solution too.
Also, how could I make it so that when a block is destroyed, Ie: dirt, a piece of dirt gets put in the first available hotbar? That would then allow me to put the first questions solution to use.
So, getting items in inventory, then allowing the blocks/items to be placeable is my question. Help would be greatly appreciated.