How do I set custom launch options?

0:141:19How to set game launch options | Steam: New update – YouTubeYouTubeStart of suggested clipEnd of suggested clipSide right down here launch. Options simply type in launch options that you want here. And thenMoreSide right down here launch. Options simply type in launch options that you want here. And then after doing that simply close out of this window. It should save automatically.