scroll tablet How do you mount and unmount when it doesn't show unmount option

have got a scroll tablet

I can mount it ok but when it is time to unmount it nothing comes up. It says turn of internal device and then gives a message to remind to unmount it

Need any advice plzzzzzzzzzzzzzzzzzz

Someone said if you pull down the thing at top there is a option but there is none on mine. Is there anything i can do in the settings and also can i unmount from my computer and how do you do that

love it just wish could watch videos on it. Also anyone know a good youtube downloader for it?