Rudolf Heijink (rudolfJan) published this series of three tutorials destined to aspiring scenario authors.
Part I is an extenvive beginners guide, that leads you step by step through the process of creating simple scenarios. It comes with sample scenarios, an extensive table of contents, 50 illustrations, index and glossary.
Part II covers advanced topics regarding scenario creation.
Part III covers creating LUA scripts.
For your convenience, all files have been packaged together in a zip file available from the RWA file library.