Agree with @daisyjgrey the snacks type depend on your children's age.
Mine eat 3 meals a day with 1 snack sometimes just because I'm very conscious about their dental health. I give them a solid 2 or 3 course at lunch and dinner with protein to make sure they can last til the next meal.
Snacks that I buy/make but are often eaten with a meal:
Fresh coconut pieces, fruit, mini vegetables, cucumber, Dried unsweetened coconut flakes, sugar free jelly, Greek yogurt with desiccated coconuts or flaked almond and honey, strawberries and cream, frozen fruit and cream or yogurt, olives, garlic prawns, guacamole/salsa and tortilla chips, smoked salmon and cream cheese, frozen banana lollies sometimes dipped in chocolate, smoothies, tzatziki and mini toasted pita and veg sticks, cold cooked chicken tikka slices.
So it would be: breakfast at 7;30am, lunch at 12pm, snack at 3;30 and then dinner at 6-7pm and bed at 10.