diff --git a/download-subtitles.lua b/download-subtitles.lua
index e3c5e4b..7de37a4 100644
--- a/download-subtitles.lua
+++ b/download-subtitles.lua
@@ -1,5 +1,8 @@
 #!/usr/bin/env luajit
 
+-- requires chromium installed and usable
+-- expects a single argument, a playlist to download subtitles from (channel URLs work as playlists)
+
 local source = arg[1]
 assert(source and #source > 0, "Specify a URL!")