Welcome to the forum! There are a lot of great people here willing to lend a hand anytime. Often using the Advanced Search box (at the top of every page) will lead you to the answers you're looking for. If not, feel free to post a question in the appropriate area.
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With respect to your question, generally video supersedes anything else the iPad is doing. However any open apps should go into a wait state. When you close the video, tap the home button twice and the apps should be there. Tap on any one of them to reactivate it...it should reopen in the same state it was in prior to playing the video (or running another app). Is that not the case? If not, perhaps some others will chime in.
Welcome again and enjoy!