Hello, my name is Dan.
I will do my best to help you, the only stupid question is the unasked one.
It is difficult to go back, it is possible but I do not that necessary.
First go to Settings/Wi-Fi, make sure it is turned on.
Then there should be a list of available networks, hopefully one is yours, tap it and enter the network password.
It should take it from there.
Now as to the Apple ID/iTunes ID under Settings scroll to iTunes & App stores.
Tap that, the next will have a blank for your Apple ID, type it in exactly as it is in iTunes (your iTunes email address, the entire thing), then your password XXXXX iTunes (pay close attention to any caps).
There is also a place to tap 'Forgot Apple ID or Password, use it if your info does not work.
This is the manual for iOS 6, it shows what I describe above.
Let me know if that helps or not please.