Ash/Kaiden has been taken straight to the hospital area near the bottom floor. There's no "action" to speak of but it's really here for side missions and item shopping depending on how much credits you earn. However, it might be ideal to build up further on the Paragon/Renegade streak.
You only have access to the hospital and the embassy. Start with the hospital. There isn't much but you can recruit a doctor and giving happy or sad words to Ash/Kaiden. The added benefit is buying gifts to increase the love interest in the hospital bed.
In the Embassy, you can talk to Commander Bailey about his status and the reporter who went out. Anyway, you can't start your open space mission without going into Council Udina's office. If there are reasons why the alien races can't help Earth is simply their own planets have problems. So starting with the turians, your job is to find a turian council and find common ground later in dealing with the krogan and the salarians.
The reporter near the elevator of the embassy will give you two choices. The renegade option comes earlier, showing Shepard knocking out the news lady! But if you wait until the paragon sign shows up, she'll be part of your War Asset. But if you let the conversation run until the end, you totally blew it and you'll never see her again. You can also talk to James Vega for his thoughts on the war. And coincidence or not, whenever you hear people and aliens talk about something important as a side quest, you automatically got the codec which you can check up later.
The other reporter Diana Allers is located near the exit of the Docking Bay. Perhaps it's important to note that without her, you won't gain anymore paragon/renegade in three key points: After the genophage cure, Citadel under siege and the asari/geth war. And if you are a male Shepard, if you play your cards right, you get to sleep with her. Why waste this chance? It will help build up your reputation.
As the game progress, you'll have more access to more levels, more side quests and more items to buy at certain times. Perhaps it's worth mentioning that certain side quests will not be access after the Citadel gets attacked by Cerberus after the turian, krogan and salarian war. This is the summary for people playing this area the first time so memorise where you need to go. Once there's nothing left to do, you can exit the docking bay to go on the Normandy which also acts like the Citadel.