New to Visio

[rhfjr]

I am new to Visio and trying to figure it out on my own. Is
the book Visio for Dummies a good place to start for
learning Visio?

Second, I started by trying what I thought would be a
simple drawing.

In the Irrigation stencils I selected a pipe and back flow
preventer.

I wanted to glue the back flow preventer to the pipe. How
do I get the pipe and back flow preventer to be the same
true scale?

Do I need to measure the length of the BFP to do that or is
there a way to download those specs form the mfg?

Thanks