Update README.md (#553)

I made more clearer how to use the keys

README.md

@@ -18,6 +18,8 @@ Now perfect for everyday use.
 
 This application contains no ads, doesn't make any network requests and is Open Source.
 
+Usage: to apply the symbols located in the corners of each key, slide your finger in the direction of the symbols. For example, the Settings are opened by sliding in the left down corner.
+
 | <img src="/metadata/android/en-US/images/phoneScreenshots/1.png" alt="Screenshot-1" /> | <img src="/metadata/android/en-US/images/phoneScreenshots/2.png" alt="Screenshot-2"/> | <img src="/metadata/android/en-US/images/phoneScreenshots/3.png" alt="Screenshot-3"/> |
 | --- | --- | --- |
 | <img src="/metadata/android/en-US/images/phoneScreenshots/4.png" alt="Screenshot-4" /> | <img src="/metadata/android/en-US/images/phoneScreenshots/5.png" alt="Screenshot-5" /> | <img src="/metadata/android/en-US/images/phoneScreenshots/6.png" alt="Screenshot-6" /> |