To re download previously purchased apps go to the purchased list in the app store. Look for apps not on this iPad and select the one you want to download. Touch the cloud symbol to begin the download. You may get a pop up that asks for your Apple password, enter the password and the download will begin.
Wow, I never knew that!
Once I wanted to delete an app for space for a bit, then I wanted to redownload after, but I wasnt sure if I could regain it or not. Thanks for the advice!