Add instructions for ffmpeg installation in windows

Author: casualsnek

README.md

@@ -21,8 +21,14 @@ Download Latest 'onthespot_linux' from the release section and execute with
  ```
  ## On Windows
 Download Latest 'onthespot_win.exe' from the release section and execute by double clicking the downloaded file
-If your downloads gets stuck at 99% and ```Converting``` on progress text, you are missing ffmpeg ! Please install it
+If your downloads gets stuck at 99% and ```Converting``` on progress text, you are missing ffmpeg ! Please install it by following the instructions below
 
+### Installing ffmpeg in windows
+- Open Windows Explorer and Navigate to ```C:\`` Drive and make a folder name ```ffmpeg``` there
+- Download ffmpef zip from [https://www.gyan.dev/ffmpeg/builds/ffmpeg-release-full.7z](https://www.gyan.dev/ffmpeg/builds/ffmpeg-release-full.7z) then copy the ``bin`` folder from zip to ```C:\ffmpeg```
+- Open CMD as administrator and run the command: ```setx /m PATH "C:\ffmpeg\bin;%PATH%"```
+
+Now the application should work as expected
 
 If you have ideas for improvement/features create a issue or join discord server for discussion !