Yes you get 500 calories per day on a fast day (if you are female, males get 600 calories).

You can eat whatever you want, you don’t have to restrict carbs, although some people choose to. The recommendation in the 5:2 book is to eat some solid protein and vegetables on a fast day and avoid empty calories like sugary foods and drinks. You can eat 1,2 or 3 meals as long as you stay under 500 calories for the whole day. Some people choose to do water fasts and consume no calories – that’s not for me, but some people say they find it easier to eat nothing than just a little. The way you consume the calories over the course of a fast day is entirely up to you. I choose to eat dinner only on a fast day and I allow 1/4 of my calories for milk so that I can have an unrestricted number of cups of tea throughout the day – I find if I can have a cups of milky tea through the morning and early afternoon I don’t miss the food. Everyone has their own method – you really have to try a few options and find what suits you. My only strong recommendation is that you plan the bulk of your calories for the time(s) of day when you know you are always hungry as this will be the most difficult time to do without food. I get hungry late in the day so allocating most of my calories to dinner is sensible for me. If I was someone who was always ravenous at breakfast time then this option would work for me.

To work out the calories, carbs etc in food you need to either put an app on your phone or find one of the free internet nutrition tables. Some options are:
http://www.weightloss.com.au/diet/food-nutrition-tables/food-tables.html
http://www.calorieking.com.au/
http://www.myfitnesspal.com/food/calorie-chart-nutrition-facts
There are many more besides if you want to do a google search.

You can cook any foods that you like that fit within the calorie limits. My main choices for meals on fast days include: stir-frys, omelettes, salads, grills, curries and soups. What I make depends on the weather and what I’m in the mood for.