So you're going to be in the mountains for ten days. What do you take with you?
In our case, it was "as little as possible". A couple of pairs of jeans (despite the heat, I still prefer jeans for hiking), some shorts, underwear, tshirts, a pair of flip flops.

You need a sleeping bag. When I was doing it, materials science wasn't as advanced as it is now, so you were very lucky to have a high tech light sleeping bag. Mine was a pretty good one. Tent? Fahgeddaboutit. It's December! It
never rains in December! We'll sleep under the stars. One of those
sleeping mats
is essential. As is a
survival bag. On my first trip, I had an external frame backpack. It was useful, but not the most comfortable thing to hike with, and it made this
clinking noise with every step. Drove me nuts.
clink clink clink. Duct tape would probably have fixed it, but for some reason, we neglected to bring any. I see nowadays it's recommended. Probably due to some
clink related death previously.
On my second trip, I had upgraded to a lightweight internal frame backpack. It was a dream to use. About the only thing bad I could say about it was that it makes your back a bit sweaty.
Into your backpack goes all your clothing. If you've done it right, you still have a lot of space left. some toiletries and a small first aid pack get added to that. The sleeping bag gets strapped on top or stuffed in, depending on your sleeping bag and backpack. And your mat straps on the bottom. Then you weigh it, mentally double that for the food you'll be carrying, wince, and wonder if you can hike naked. You can't.
The food. I'll talk more about the food in future posts, but essentially, you have to carry it all with you. I think they give you one drop point that you can make a package to resupply, but that's about it. At the start of the adventure, they give you this pile of food, and it's your job to make sure you don't starve. So you portion it out amongst you, weighted to the older folks and go from there. Pots and pans are irrelevant. You have a combination pot-bowl-plate-cup thing that also holds your utensils, weighs very little and is probably about 15x20x10 centimeters. It'll do. There's always the Dutch Oven base.
Cooking is done on those tiny camp stoves. We carry a couple of them and a few refills.
I agonised for days over what I was packing and what I needed. In the end I think my backpack (both times) weighed about 20 kilos, or over 40 pounds. For someone not yet 15, this was considerable. If I fell over backwards, I was like a turtle and had to be helped up again. It's not as bad as it sounds, because a good backpack puts most of the weight on your hips, but you better be fit, and you better have worn your hiking boots in.