Block in client side

hello, do not tell me how I could spawn a illusion block from the client side only. this is necessary to implement the visualization of building schemes

I have never tried to spawn an object but only from the client side. the player will hold the blueprint, and a projection will appear on the block they are looking at. but, I don't want other players don't see this projection. the projection will be a simple block, for tests you can use oak for example