I’ve recently bought this Kidzshack cubby house (https://kidzshack.com.au/products/happy-shack-pre-order-2025) - it’s the ground level version not the elevated one and is 1300 wide x 1100 deep. The cubby has a floor but my question is more about the base or foundation on which to sit the cubby on to ensure it’s protected from moisture and sits level and is stable. The company was not particularly helpful with specific advice other than to say put to pavers underneath.
I’d like to put the cubby in the back corner here where the white rectangular planter currently is. This area is about 1560 deep. There is just bare soil here and I don’t think it’s very even.

My question is can I simply place the pavers on top of the soil? I’ve gone down a bit of a rabbit hole of looking at the how to lay pavers guide but I think this might be beyond my DIY skills. I need a simple but effective way to create a base for the cubby.
Based on other posts I’ve read, one approach I was thinking about was using a tamper to compact and try to level the soil, then placing pavers on top. Will this be too unstable? Would adding some sand underneath help? Would the sand also need compacting and would it require a frame?
I’ve also been looking at this product (jack matrix fast floor) and wonder if placing this on top of the pavers would give an extra layer of protection from moisture?
Are there any other simple options you would recommend?
Thanks for helping this DIY novice mum out!