Gee, thanks a lot...
I was wondering whether I played it the wrong way or not... Now I'm in 1982 and have captured 1 Leader so far. Well, that's enough for the scientist to get to work.
As for the bases, do I need to "deliberately" let some medium alien vessels land repeatedly? Is patrolling necessary to detect them? And will the bases develop in size if left alone for some time?
EDIT : I've just found this Link. It contains alien invasion progression. It stated progression from month 1 until 10. Is it in a recurring pattern or like "unlockables"? And is it still valid if I use is as reference for the Community Edition?
PS: I do badly in playing strategy games as I tend to build economy *cough* safety *cough* first and ended up defeated by continuous light raids or badly besieged in late-game. So I expect some difficulties in playing the ground missions. That's why I picked Easy but still do quite miserably in terror missions.