Newbie to Visio -where to start

[bnath001]

Hello Good folks

Used Visio once or twice long time ago.

I need to produce a diagram using Visio.

Where can I download Visio from? Is it free?  I have windows 8 on my laptop.

I need to put together a network diagram that using Big IP F5 product in the diagram.

Any pointers or leads on where to start would be a great help.
Kind regards

[Surrogate]

Hi !
MS Visio is not free product !
You can get trial: Visio test-drive