How to Reinstall using Steam

[vcplz]

I was trying to install the White Night Custom story and I believe I did something wrong. At any rate the game files have been corrupted and I need to wipe the slate clean.

I'm using a mac on steam. How do I reinstall the game?

the exact same thing happened to me so I right clicked on the icon an delated local content but dont worry the game will still be in your game library so you can just re-install it and you are done
I freaked out when that happened to me cause amnesia is my favorite game and not to mention all of the custom stories i loved playing i was devastated