So, you want your character to shoot a projectile to your mouse position?
It would be the exact same as the movement in the TPS project. Instead of making your character move on click, have him shoot a projectile at the Mouse Hit Result.
If you meant having your character shoot at a target, it’s even simpler. Choose the target you want to shoot, make your character face said target, and spawn projectiles.
I hope I understood what you asked.