Therein lies lifes biggest tip or trick... If all else fails- read the manual
That is if you are so lucky to have one.
It's not quite handy to stop your mission, exit the game just to read the electronic manual.
Because the game came out in differant languages, the publisher decided only to include a printed manual in the English version of the Game.
Me, living in Holland is one of the people who bought the Pre-Ordered boxed version of the game and got the Dutch version. I can read English, but only got the Electronic Manual, in form of a pdf file.
Knowing the costs of printer ink those days it's quite expensive to print out the manual (36 pages). And if you will end with a readable print-out You have to print it full size, meaning A4 format.