Here is an idea of the sort of thing you might eat in a given day if you need ideas
breakfast: oats with fruit + yoghurt
mid morning snack: a piece of fruit and/or a handful of nuts
lunch: chicken/tuna salad with a piece of multigrain bread
afternoon snack: glass of milk or some carrot sticks
dinner: aim to fill your plate with 50% vegetables, 25% protein i.e. meat and 25% carbohydrates. E.g. beef stir fry with rice and lots of vegies or steak and salad with mashed potato or something
don't forget to drink enough water and no, tea and coffee do not count because of the caffeine. Same with coke and stuff. Herbal tea is ok to count as water.