Don't quite understand what you mean by where do all your apps go? Have you filled all the available pages? If so if you do buy more apps, they'll be there somewhere but not visible. You can do a search for them by swiping right until you reach he search screen. The best thing to do is to make some folders by pressing on an app until it jiggles, place your finger on it, try to avoid the X as this will delete it, but don't worry as you will be asked if that's what you want to do, now slide it on top of another app and a folder will be created. While in the jiggly state you can change the name of the folder by pressing the X on the name line and you will be able to input what you like. Just press the home button to return to a normal screen. Hope this helps, otherwise we will need more info here.
The IPad Forum is a community of members from all walks of life and from all over the world coming together to share our experiences and to help each other learn about this wonderful piece of technology the Ipad. There is a wealth of information already here in the many threads we have so doing some searches will answer most of the questions you have. If then you cannot find the answer you are seeking then by all means post your question. There are many friendly and informed members here only too willing to help you.