Nexus Revisited & Flight to Onaon
Before setting course for Onaon, make sure you've take care of any pressing business on Eos or the Nexus- you'll be out of touch for a little bit. If you haven't been to the Nexus since saving Eos, definitely make a stop there first. New areas in the Docking Bay have opened up (the Vortex bar, Cultural Exchange Tech Lab, and Hydroponics), and the old science area in Operations now hosts a news bureau, among other things.
With these new areas come new side quests, such as Broken Wires, Better Crafting, The Fire Fighters, Programming A Pathfinder, and Boosting the Signal, to say nothing of various team-based objectives you may have acquired (most likely Drack's Krogan Betrayal task). You'll probably want to check out the new shops in the Docking Area as well, and visit SAM to unlock new memories. Lastly, be sure to talk to Addision and then her assistant Brecka about AVP.
There's a lot of in-universe justification, but it boils down to spending your progression points to get special perks, like in Dragon Age: Inquisition. I recommend aiming to get the Advanced Training perk early on- more XP is always good, and there's no level cap to bump up against later.
When you've tied up all the loose ends you care to tie, make the jump to Onaon and land straight in the middle of an ambush-slash-cutscene.
Not sure about the physics here, but it's all very exciting. Your actual dialogue choices don't seem to make much differenc, so let the narrative carry you away, into a forced landing on an unknown world.
Chat with the locals, then follow your guide through the city. Don't make trouble.
You'll meet with the Resistance leader, pick up a new crew member, and be let out back near your ship. Despite the fact that you are on an entirely new world, nothing here is worth scanning but the alien shuttles (well one of the two, at least).
There are also two quest givers. Right after you gain control on the docks, look west to see Sohkaa Esof, who will start the questline Trading Favors.
To the east, past Jaal, is Avela Kjar, who kicks off Recovering the Past, and is mildly romanceable by a male Ryder.
When you've completed all that, head back to the Tempest for a productive chinwag with the crew. After that, you're relatively free to go where you wish, but the story calls for us to honor the bargain with Jaal, so that's what we'll do next.