Very basic test

I currently trying to configure a Asterisk 1.4.5 server.
It was installed with the asteriskNOW .iso.

I’d like to understant how it works and do a quick test :

Connect a softphone on the Asterisk in LAN and I want the asterisk play the

exten => s,1,Answer( )
exten => s,2,Playback(hello-world)
exten => s,3,Hangup( )

exemple from the Asterisk doc.

May I have a simple howto to configure that the simplest way ?