To play battlefront 2 on PlayStation 4 with a friend (not on splitscreen) you will need:
Your ps4
Friends ps4
Internet connection, TV, and power connections for both.
PlayStation plus subscription for both. Link: Playstation plus on amazon Once you have the code, enter it in on the PlayStation plus menu. Yellow plus sign on the left of the home menu.
Be sure to friend your friend. (Search for their gamer tag under friends on ps4 home menu and friend them.)
To play:
Open battlefront II.
Go to friend list (top left of battlefront II home menu.)
Find your friend.
Join a game and invite them or join a game they are in.
This will let you play online with your friend without splitscreen.
Sadly, there is no way to do this without splitscreen without a PlayStation plus subscription. You can play splitscreen under the arcade mode in battlefront II.
If you need any more specific information that you can't find by Google searching it, feel free to reply and I will try to help. I do not personally play online, so I may have missed something.
Hopes this works! If this answered your question, please mark this post as the best answer.
