^What he said. It's integrated into the game. If you want to play the new new content, it's the Fleet Starbases and the following missions:
Colony Invasion (Ground)
Fed/KDF Starbase Incursion (Ground)
Fed/KDF Starbase Fleet Alert (Space)
Fed/KDF Starbase Blockade (Space)
Fed/KDF Starbase Defense (Space)
No-Win Scenario (Space)
All of those can be accessed from the PvE queue. They're all team-based missions, but if you join the queue you'll be put in a team, so you don't need to be in a fleet to play them them. But the rewards from them are Fleet Marks, which are used for building fleet starbases, which you do need a fleet for. I also wouldn't recommend PuGging No-Win Scenario unless you're a masochist.
There's also the Tholian Ground Invasion, which you have to go to the Nukara System in the Eta Eridani Sector Block to access. It's an open instance with several different missions to choose from, some of which can be soloed and some which can't. You won't be auto-teamed when you get there. It gives you ordinary loot, including a 3 piece Tholian ground set (random drop though). And if there's a Fleet Event on (check the calendar) more Fleet Marks.
Good you started the post, was thinking to open one myself. Ok, I'm gonna say something most of you won't like, but take it easy folks, it's just an opinion, not trolling, not bragging, no bs.
So, I mostly play with my Klingon tune, but I do have 2 VAs. Every now and then, I jump on the blue side for some fun. I had few fleet action with my sci yesterday. To put it gently, a failed stf is a good experience. No, not saying that klinks are much better (in fact sadly they are better as an average player, both Pvp and pve, but the number of fed players is just overwhelmingly greater), but seriously, most (not all of them obviously) fed players have no clue how to build their ships, partially because cryptic doesn't have a walkthrough about this and also due to the fact Pve is dealing with dumb Ai/npc that pose no challenge whatsoever, causing players to go through levels too easy and with worthless builds and skill tree. So again, not trolling or bragging, but everyone that dies constantly more than 2-3 times in a fleet action, should seriously reconsider their build. Especially if flying a cruiser or sci. Not only that if you die too often the fun goes away, but you are a liability for your team. Not to mention kind of embarrassing... To die from the hand of an npc... Same applies for stfs. There are many people flying through all those pve events and not dieing once. And many of those people don't even pvp, in case you'd think I imply that. And since I mentioned pvp, for those that feel like, here are some excellent links on how to build your ship. A good pvp build will always excell in pve. Probably this is why cryptic didn't pull the plug to pvp yet, some folks in there really do some hard core testing and find out bugs.