SCAR is essentially just Lua without some features (I/O, etc). There are numerous Lua tutorials out there, including the official Lua website.
As for SCAR-specific functions, you can find a list of them here:
http://fortresseuropemod.com/scardoc
It has not been updated for some time, but should have more than enough to start with.
Thx very much,I will take a look at it.