I need Help with this mod im making

So Im trying to Re-create a Minecraft mod called SercetRoomsMod the dev Abandoned 1 year ago so Im making it for new version of it in MCreator

I need help with this  so i made a custom block now i need to make it so when i place the block down it will replace itself with the block i right clicked on to place and also the block needs to be able to walk though like a ghost i need help?