How to add my PC friend from my PS4 or vice versa

Discussion
#1

I am trying to play with my friend who is on PC and I’m on PS4. I read on google that you can play the game crossplay but we cant figure out how to actually add each other on the game

#2

still waiting for them to make crossplay a thing

#3

oh okay. I thought I saw that it had been added late last year. but ig I misread the source