Make a pointer arrow that shows where player will go

I’m trying to make a clone of the Climb Up game, but I stuck at the moment where I have to make an arrow that shows direction of the player’s throw.
Here’s what I’m trying to implement

And this is how my game looks like

I tried to make an arrow from cubes and rotate It from mouse, tried to put an image of the pointer In the canvas and rotate it from there, but nothing seem to be working, so I’ve decided to ask for help.