Digital game on ipod Tunch (Free!!)

Hi guys:
I would like to introduce one interesting game about guess number.
You can guess number (4 digital) by result of response from iPod. (�A� means you got right number and right position, then �B� means right number but wrong position.)
You can train your login of mind and have fun in it. Most important is �it�s free game�
Get it from â��http://itunes.apple.com/WebObjects/MZStore.woa/wa/viewSoftware?id=298408820&mt=8â;��

I am a itouch novice. Exactly how do I get applications and games? How do I get them on to my itouch? I am 65 years old, so take it slow.