Broken Screen on S6 Active. How to pull files from it?
In normal scene it should be recognized in pc but some OEM have their phones such way that it won't be detected till it is locked 

So try to see if it is unlocked and when you are sure that its unlocked connect it to PC then on guess work you can select the usb settings from notifications and click MTP and to do so refer to s6 usb/MTP settings  videos(youtube) and tap exactly at the screen as in videos and you should get it