Hi Laloop & welcome
It basically works like this:
Green days - eat as much pasta, rice, potatoes, cous cous, lentils/ beans, fruit and vegetables as you want.
Original (red) days - eat as much chicken, beef, turkey, lamb, pork, ham, fish (including seafood - prawns, crabsticks) etc, as you want and fruit and vegetables (be careful though as not all vegetables are free on red days - sweetcorn, potatoes, lentils, beans etc aren't).
On both days you can eat as many eggs as you like. Which is great for lunch times when you can't decide what day to go with!
Every day you also choose up to 4 Healthy Extra's (2 x HE a's and 2 x HE b's) The 'A' choices are dairy products, cheese, milk etc, and the 'B' choices are usually bread, cereals, meat for green days, potatoes & pasta etc, for accompaniments to red days. These are all measured amounts.
In addition to this you also get 5 to 15 syns a day to use on anything you like.
It sounds confusing but once you get into it, it really is very easy. The website has the Healthy Extra's listed and also has a syns database/ calculator that you can use to find out the syn value of your favourite foods. I would really recommend you buy the magazine as this is one of the best ways of getting to grips with the diet. It includes a 7 days menu plan and also new foods that are either free or low syn. Stay away from Mix2Max & Success Express for now until you've got to grips with this.
If you've got any more questions, feel free to ask, everyone on here is really helpful. I hope this has helped and good luck.