Well Hello,
first sorry for Bad English…
how can i destroy a Pandora Base ? When i enter the Base i have to destroy the Brood Chamber… but there is no Chamber… I kill all the Aliens again and again but there is noch target oder something else that i could destroy… so a wave after another spawns and i have to retread… Do i have to destroy a little base first ? or is there something to research first ??
The game is difficult, especially for someone who hasn’t played other similar games before. I suggest you play the game on the lowest difficulty - it will still challenge you but the pace will be a little more relaxed.
For the missions I think you’re speaking of - killing a pandoran spawnery:
It is a big bug that is in a squarish hole in the ground - usually in the furthest left or right corner of the map, in my experience. Identifying the hole: it will be flat, with no vegetation or rocks/spikes sticking up. The hard part is that the pandoran maps are difficult to navigate and you cannot see the Spawnery until you are right next to it.
If you are having real trouble you can save the game and try using your Heavy to Jump Jet near where you think the spawnery is. Once you’ve located it then you can reload the save game (or if you have to restart the mission). When you get to it all you need to do is kill it and the mission ends (which is important because there are always lots of enemies).
Hope this helps
This turns out to be not always true. I drove myself nuts looking for a spawnery on one map, checking out every hole, but it turned out the spawnery was on a small plateau, right back near the edge of the map at a corner. My trouble was that I didn’t recognize it because I was expecting it to be in a hole.
I’am a X-Com Veteran (old and new one)… I searched on the map for about 20 Minutes with every soldier class i have (heavy included), there was nothing i can shoot on, or get marked when i get near to them. I saved the game seperated, so i will search again… but it would be nice if someone can send me a screen of this Spawnery
I assume you are talking about the Lair. If so, the Spawnery is usually in an oval hole in the ground at the extreme left or right corner of the map, furthest from you - usually the left. There is usually only 1 or 2 ways in, and you cannot spot the Spawnery until you are right on top of it - it looks like a giant Hermit Crab.
If you are talking about the Nest, that’s different. These usually have 2 Spawn Sentinels - tall alien towers with fronds on top that look like extremely thin Coral Polyps or Anemones. They generally have about 250 HP and require about 3 or 4 shots to take down.
'Fraid I can’t help you with a Citadel or anything later as I haven’t got that far yet.
Good luck 
Here’s a pic of the Spawnery from a different thread.
Thanks now i know what i have to find… and in my Save game there is no such creature… maybe bugged…