whatsapp

m using samsung galaxy J7 prime - jus reloaded the whatsapp - all my chat contacts are gone - now hv a few recd chats but i cant view the video attachments - when i tap on the attachments "to download media, allow WhatsApp access to your device's photos, media, and files . Tap Settings - Permissions and turn Storage on

when i tap on settings - its goes into application info and i go to Permissions (No permissions allowed) and tap on it which leads to App permissions with WhatsApp with Camera, Contacts Location, Microphone, Phone Sms and Storage and when i tap on Storage - its says "Screen overlay detected to change this permission setting, you 1st have to turn off the screen overlay from Settings - Apps and when i tap on this it leads to Apps that can appear and i am lost from here

how do i turn off the screen overlay

thanks