macro's for dummys

Have been working with some Control Technique (Emerson) and Maples HMI units and they both have the ability to create a custom macro.
In a couple of applications i used a custom macro that basically tech support at Emerson and Maples assisted me with getting to work.
I am interested in learning more and wondering if someone could give some suggestions as the best way learn about programming macro's?
Not really familiar at all so a Macro for Dummys type book would be great.

Make HMI's submit thru macros

It's mostly just plain C with a little Basic. I say this because the way macros in Maple handle strings. I got a good ref book on C that starts mellow then dives deep and has a lot of examples about manipulating/handling strings. Do your calculations with macros; less data type truncation problems, and Maple has built-in options to filter input values. Don't get crazy with running a lot or large macros they will affect HMI performance quick.