added usage

Author: tb582

README.md

@@ -2,3 +2,9 @@
 windows batch file to run ffmpeg
 
 We'll take FLV files with SPEEX audio and transcode it into a playable MP4 with AAC audio!
+
+## Usage
+In the directory where your souce files are.
+```
+curl -O https://raw.githubusercontent.com/tb582/ffmpeg-batch-encode/master/ffmpeg%20FLV2MP4.bat
+```