Re: how to delete media and files from phone mem.
What phone are you referring to?
If it is a Windows Phone 8.1, then you could launch Storage Sense and then tap on "Phone". You will be shown different categories for all the files in your phone, from "apps+games" to "other". You should find all your media files under "Music", "Videos", etc. Tapping on any of those categories will bring you to a page where you can either manage or view those files - or delete them if you don't need them in your phone anymore.
P.S.
This should be in the Windows Phone section (if you're using a Windows Phone), not in the Tablets & Laptops.