Lua question: Need a Lua tutorial

Hi All, I'm documenting the CGI on the Linux side of the Yun. It appears to be lua. However, the code offers very little clues as to how it works. If anyone can point me towards a Lua tutorial, I could figure it out. I just don't know anything about Lua whatsoever. The code is below.

TIA Jesse

require "luci.cacheloader"
require "luci.sgi.cgi"
luci.dispatcher.indexcache = "/tmp/luci-indexcache"

Currently I'm reading this: Lua is a fun little language although it isn't well known by many people (including me)

kind regards,