If your kids are uneasy at the idea of sleeping outdoors the first time, set the tent up in the backyard where they feel secure and they will get used to outside sounds and make it an adventure.
Kids love adventure, there's no better place than better out in the great outdoors with fresh air and nature. They will come home with a better understanding nature and wildlife.
Young kids can be a lot of work but it sure is worth it, their face lights up when they see something new and exciting.
Take plenty of photos; they may not remember, at least you can show them. Take some close ups of them fishing, setting up the tents, cooking marshmallows on the campfire and any other activity they love to do.
At night shine a torch up into the trees, some eyes might shine back, if you're lucky a few animals may come in close looking for scraps.
Kids love playing with glow sticks or torches at night.
Let kids be kids, let the adventure begin. Go for a walk around your camp let them discover their new surroundings where ever you may be.
Later in the day let them help set up a safe campfire providing you can have one.
Remind them that all litter gets picked up and disposed of properly.
Show them how to do jobs around the camp that they are capable of doing, they could setup their bed the way they would like it to be.
It's a good idea to bring a few familiar toys & books so they can have with them when they go to bed or need comforting.
You could bring a new game or pack of cards, coloring book pencils etc. if they need distracting at some stage
Always watch them near any pool, creek, river or any water source. Water is always an attraction.
Kids soon make friends with other camping kids, take a ball game they can all play.
You may have room to take a bicycle, remember the helmet.