Update README.md

Author: Oil3

README.md

@@ -4,7 +4,8 @@
 An extension for MacOS' "QuickLook" which allows .webm movies to be played in the Finder and Spotlight previews like any other movies.
 
 
-To install, launch "Webm Quicklook.app" once.
+To install, launch "Webm Quicklook.app" once, seeing the sample video indicates success. 
+You can close the app.
 Keep the app somewhere: the way QuickLook extensions function today is by being inside an app, this is Apple's rule, and it is so to ensure that mac plugin also go through Apple's app security review.