Can you describe your question? I cannot understand what you mean.
Do you mean than, when you open it, the menus are hidden and you do not know how to close it? If so, hit the escape key, then close it.
Yes this is correct. But I also like to have a buttom inside this PDF document where I can closed it from.
Create a button in InDesin, attach View Zoom action to it (the last one on the + dropdown) and make sure Zoom-option is set to be Full Screen.
That way your button will work as a on/off switch for full screen mode. If your PDF is not on full screen mode it will switch it to full screen, if your PDF is on full screen, it will switch it off the full screen mode.