Everyone does it differently. The best 5:2 is one that you can do with minimal effort. Easiest starting point is to eliminate all added sugar from your diet. No soft drinks. Drink water. No sugar in your coffee/tea etc. No processed grain based foods. So no bread, cakes, pasta, pizza, biscuits, rice, breakfast cereals (pure junk) etc. No fruit juice, pure junk. You want fruit have real fruit. No honey What to eat? Lots of veggies especially cruciferous veggies. No potatoes way too much simple carbs in them. Some fruit like tart apples and berry type fruits. Some real cheese and high fat low sugar yogurt. Lots of legumes and beans. Go to snack, have nuts and seeds. Almonds, walnuts, pecans, brazil nuts, pumpkin seeds. Some tuna or occasionally some red meat or chicken.
Breakfast: two tablespoons of yogurt, 2 cut up strawberries, handful of almonds and pumpkin seeds. Or Bacon and eggs no toast
.
Lunch: tuna salad, dinner leftovers.

Dinner: homemade veggie curry with lots of lentils, beans added. Nice piece of cheese for desert.

Snacks: Nuts, an apple some cheese.

If you are addicted to sugar/sweets then it will take about a month to break that addiction. It will be tough.