How to open developer mode in Samsung J7 and connect it to computer for file transfer. If you didn't succeed with this video try
this one https://youtu.be/uzU_EPhrgmc

or MobileGo software. Links for downloading mobile go software:
PC version: http://bit.ly/2nPqwQE
MAC version: http://bit.ly/MobilegoMAC
This is the trial version. If you like the software purchase it.
Usually phone will not show when you connect it to computer even if you have latest drivers and PC Suite.
To open developer mode and change connection type, you will need to do following as on the video.

This is the easiest way to connect Samsung J7 with your computer without paying for additional services https://www.youtube.com/watch?v=5xxiNQ-xXEw