IMHO best way probably is being in a guild.

Join Discord, add people to your friendlist. Both should be good ways to go.

Can also take a look here (Server and faction for open beta.) to see if folks are on your server. May need to join a more popular server. Also, this is a KOREAN open beta test. There is no catering to English speakers. Unfortunately, you should expect to find parties a big challenge unless you join a larger English speaking guild.