Aion Stuff

Hi everyone,
I checked on some sites and also here but i cannot really find the info im looking for… but maybe its because im a bit lost on the topic and dont really know how to ask my question.

So, here is the deal. How does it work in Aion for the instances? What kind of instances is there at the moment? Where are they ? How many player can participate?
Thing is im a bit confused and mixing up things between the different type of missions. Is going in the abyss the only way to do instances ? Is the capture of fortresses the only kind of instances? And what about the rifts ?
:dizzy:

Sorry for all those questions, if it was already asked just forward me the link cause i didnt find in this jungle of post…

Thanks in advance for your help