A UML Tutorial Introduction

Looking at UML again, it is one of these things that I will eventually have to do, if I want to do a more universally readable design

After finding this: http://programmers.stackexchange.com/questions/114689/best-free-on-line-resources-for-learning-uml
I then go to this:
A UML Tutorial Introduction

And then this:

Will have to just buckle down and get on with it.