This guide to S3D was written by a member of the Makergear google group (Jin Choi). (Not me.) He requested it to be posted here as well, so here is the original post and link:
I have written a completely unofficial guide to Simplify3D geared towards people new to the software. It is based on my understanding of the software having used it for about a month.
http://jinschoi.github.io/simplify3d-docs/
Any suggestions or corrections will be welcome.