How do you show help for a parameter in an ArcGIS python toolbox?

Question

I have created a python toolbox, the interface is shown below:

My tool

How do you edit the parameter description so that when you click in the boxes, a relevant description will show up in the tool help?

Answer 1

You add a description to the parameter which shows up in the help panel by editing the Item Description of the tool.

Right click on your tool and select Item Description

Setting Item Description

You then add text to each parameter under the syntax section.

Syntax section