Why no parties

[Odd]

I trying to catch up on main story quest mostly just been leveling through fighting how do you unlock the dungeon runs

The vast majority of dungeons will unlock naturally as you progress through the main story. The first one will be the last level 16 main story quest you get.

[Niwashi]

The first one will be the last level 16 main story quest you get.

First one's at level 15. (Sastasha = level 15; Tam Tara = level 16; Copperbell = level 17). But yes, like most dungeons in the game, they're unlocked (and then required) by following the main scenario quests.