Create a mapping node with t-beam step by step

Hi there,
is there someone who could give me a step by step guideline how to create and setup a t-beam as simple as this manual?

I have 3 t-beams, two with the newest Version 20190612 (I use it for flarm) and the earlier one and I like to use one as a mapping node but I could not find a simple instruction or video how to do from start to end.
Thanks in advance for helping.