I had the same trouble when I started using Sendmail to do something for my organization. After a while I relized why there was no simple how-to. There are so many things you can do with Sendmail and everybody needs to use sendmail a little differently. The "simple how-to" would end up being a thick booklet. The only way to do it is to start reading the documentation. read the man pages. type
man sendmail
that will get you started
go to
www.sendmail.org There is plenty to read there.
use google. If you have specific questions that you have searched around for and you just can't find it then ask us.
I know that's not the answer you wanted, but it's how I feel on that.