iOS doens't not have a traditional file system and thus "files" are hidden from view. If you want to see them, then you have to jail break your iPad. There are subforums here that cater to that.
I have deleted your duplicate posts as this fragments discussions and is against the forum rules.
The iPad doesn't have a file system like Windows so exploring the file system isn't as easy as you might imagine due to files being stored as data with apps and the apps are sandboxed for security. Others may chime in here with other information.
There is lots of good advice and info on here plus plenty of members all too willing to help with any problems.
Remember, search is your friend. If you can't find the answer you need and you post a question then give as much info as you can to help members help you i.e. iPad 1 or 2, iOS version and name of app if the problem is with a specific app........and please don't forget to read the rules http://www.ipadforums.net/forum-rules-help-info/2119-forum-rules-everybody-please-read.html
You can download the manual for your iPad here http://support.apple.com/manuals/ and in iBooks search for "iPad user guide for" and you will find free comprehensive manuals for both iOS 4 and 5.
If you have other Apple products or are interested in other Apple kit then why not join our sister forum too at http://www.appleforums.net/