Spoiler alert- this will end up as an Architect fight, so gear up accordingly. Note that this is maybe the only fight in the game worth farming- the Nullifiers here drop tons of high quality mods and loot.
After the Kadara outpost has been established, talk to Christmas Tate in the uppermost room of the complex. He'll tell you about colonists that may have started a Remnant-worshipping cult.
Which sounds cool, but once you go check it out, there's just one guy, and he's already dead.
Read the datapad in the grass next to him. Your dialog says 'Report back to Christmas,' but your objective tells you to take down the Architect you can probably already see undulating in the sky. Might as well, since you're here.
This Architect uses the standard cycle of leg attack, head attack, clear Remnant, but its summonees are Nullifiers and Breachers, so don't expect to take them all down instantly. The environmental hazard of this fight is the acid geysers, but they're not that hard to avoid, even for a vanguard. They're even less trouble for a sniper or other long-distance build (a good config for any Architect fight) because they tend be clustered very close to the Architect itself.
Kill it as normal, and interface to send it into orbit.
Follow up with Christmas for a modicum of closure.