Hi, I am trying to plan a camping holiday with my family. What supplies do you suggest I purchase or pack?
For the camp you will need a sleeping bag, a pillow, a flashlight, a tent and tools to set it up. 
You should take enough food and water for the trip, which is probably more than you think. you will also need a stove and fuel, bowls, mugs and eating and cooking utensils. Keep in mind that you'll have to clean you utensils, for that you should take a bin, soap, a sponge and trash bags.
If you will be far from civilization, a large powerbank and solar cells will help you to charge your electronics, and a first aid kit, compass and map could be of great help in case of emergency.
Consider the weather of the place where you will be camping a take adequate clothing, footwear and hygiene items.