Forcing screen to be a certain size

How do I make it so the screen is non fullscreened (cannot be full screened) and is a certain size ratio (aspect ratio i think it is)? I tried tinkering with the player settings but with no results.

 

Through scripting, via Screen.SetResolution. However, width/height ignored when testing in the editor.
https://docs.unity3d.com/ScriptReference/Screen.html

In order to get the Player Settings Width/Height values to work, after you already started a build:
https://forum.unity.com/threads/def...eing-ignored-after-build.500178/#post-3254151