iPhone 3gs, iOS 6.0, Straight Talk APN settings with iPhone Configuration Utility

ok the title is pretty long but it gets the poitn across. I am in need of assistance. I recently sqitched carriers to Straight talk and am having trouble with setting up the APN settings on the phone. I made the mistake of upgrading my Ios to 6.0 and now I cant get into the APN settings to change them so where I can use Straight Talks data ability. I have read around and found out that I can change them via the iPhone Configuration Utility software but I honestly do not know how to work the program or how to to change the settings on the iPhone with it. I used the following link to show what I needed to change but all it gives is the information. Not where to put it. It doesn't say where to put it in the iPCU, I did find a couple of spots but I honestly dont know how or where to export the finished file or even how to save the file to be honest. I am a complete noob to this and would very much like to see a tutorial video on how and what to change to what via the iPCU from start to finish. If someone can provide a link to a video on youtube that would help as well. thanks.

the link I am using to get the information from straight talk is http://www.straighttalksim.com/support.php

I would also like to say that i DONOT want to jailbreak my phone. One reason is because I don't trust any programs that you can download onto a PC to do the jailbreaking. so that is out of the question. Do not even suggest jailbreaking to me.