Well, if you just move the cursor on the Question Mark, you'll get explained almost everything. The only actual things it doesn't tell is how Events exactly work (bottom line is, you write an equation made of the in-game aspects, for istance country population, traits evolved or events happened, all of these are under the voice "variables", then there are actual numbers and finally random numbers, where RNG just makes a number between the two limits you give him). That's about it actually, you select a template in order to make a fundation for your disease, then you can alter any aspect, create Events, traits and governament actions, wich can as well show an image from your computer(must be JPG and of specific size).