river, the basi rules are something like this:
You can have green days or original (red) days. There are lists of free foods for each day and a list of food that is free on both.
Free in green days are potatoes, rice, pasta, beans, stuff like that.
Original days is fish, lean meat etc.
Most fruit and vegetables are free on either day, as are eggs and quorn (most quorn products anyway).
Also, you are allowed 4(?) health extras - 2 from list A and 2 from list B - and 15 'syns' per day.
Healthy extras 'A' are milk and cheese (measured amounts)
Healthy extras 'B' are bread and cereal and some that change, depending what colour day you are having. For example, on a green day you could have a certain amount of meat and have it as a healthy extra. Or on a red day, you could have some pasta and count it as a healthy extra.
Every food has a syn value and you can get a book that lists them. You are allowed upto 15 per day or you can save them all for the end of the week. A creme egg is 8 1/2 for example.
Hope this makes some sort of sense, it all becomes clear once you actually do the diet. You do have to go to classes though otherwise you don;t get the book that tells you what all the free foods are!!