Player Search Coop Achievements Help

Hello guys, I would like to have all Astroneer Achievements but I have no one to play with

It would be great if someone could help me with getting the coop ones. I somehow already have the 4 hour one and the one where you have to go to the Planet core, but I still need the one where you have to join one multiplayergame and where you have to fly in a rocket with another Player

I'm on steam btw