HELP How do I start Python?

[GaryTaig]

My knowledge of Linux is purely academic - that is, I know WHAT it is. 
However, when it comes to detail, I still think IBM PC and compatible, 
after 30+ years working in that area. Very little Linux has rubbed off 
over the past few years.

I need to start Python and don't know how.

I'm using Ubuntu 10.04 Lucid which had Python v2.6.5 installed. I needed 
v3.2 and installed it using the following code.

sudo add-apt-repository ppa:fkrull/deadsnakes
sudo apt-get update
sudo apt-get install python3.2

That produced about 100+ lines of output in the terminal window and each 
activity reached a conclusion - there were no errors etc.

Before I continue with my project and following more instructions I need 
to be sure that Py3.2 is installed and working. Note: I'm following 
fairly explicit instructions but it doesn't involve this really basic 
stuff. The author has to assume a certain amount of basic knowledge.

In my Applications Menu the Programming Tab contains four items:
- Bless Hex Editor
- bpython
- DrPython
- CompoZer

I may have opened one or two over the years but like most other stuff 
with Ubuntu, I've used none of them. Anyway, none of these starts 
Python, either 2.6 OR 3.2.  I would have expected to see a menu item? No!

Python3.2 is scattered everywhere. I've searched the entire disk for 
files that are python3.2 related and found many files, directories, but 
I don't know or which files to use to start the ball rolling. I've found 
Executables, links to Executables, links to scripts, lot of stuff.

One doc I found talks about the importance of usr/bin/pythnx.y and yes, 
I have many of them.  There are Python Executables for versions 1, 2, 3 
and many other files in that directory but just looking at those is 
meaningless. If I was using an IBM based machine I would use an exe or a 
batch file. I was writing batch files in my sleep in 1982 but when it 
comes to Linux I have no idea what starts an app running.  Some help in 
that area might start the ball rolling for me.  I can follow trails, 
read files, understand simple English (and complex) but where is that 
starting point and since Python3.2 would appear to be installed, how can 
I set up a little script that runs it each time?

Perhaps more importantly, how does any other program know? Is there a 
procedure that's followed by all programs when they call upon the 
services of another system?   In DOS based systems we had an environment 
variable called a "path". This path was searched every time a command 
was issued.  Stored somewhere in a directory in the path you would 
expect to find the EXE or the batch file needed to start a program or 
task running. Or, you'd set it up that way.

What happens in Linux?

Where is the fabulous tutorial that compares all this stuff?

TIA
GaryT