Friendly battle

I need help with the friendly battle challenge. Who is willing to help?

Me! Heres what you do:

If you battle people, they appear in recent opponents, if you tap on them, there is an option to send them a friend request! If they accept it, you can battle them! Or if you have a friend, you can press Invite By Player Name, and ask them for their ID and ingame name!

Provided the friendly challenge isn’t greyed out.
I’ve been failing the daily missions because I can’t do a friendly challenge.