This tutorial shows you how to create a simple routine and how to offer support for an unknown custom field.
You need certain Java experience to do it, but we believe this tutorial is simple enough to realize how easy it is to add custom features into your katl-commons based plugin.
You can create free plugins based on katl-commns and this documentation but you cannot create commercial (paid) plugins based on SIL. If you wish to do so, contact us at products@cprime.com, and we will discuss the joined approach with you.