Base for small lightwell wall

Hello everyone,
we are planning to build a light well at our basement window. The light well itself will be built in 3 rows with a distance of 30cm between the rows and each row will have a height of 35cm. What is not quite clear to me and is sometimes unclear on the internet is how to set the first row of stones on the ground. Our landscaper said that for this height it is sufficient to compact the ground. Then apply a layer of 2-5cm of trass cement mortar and set the first row of stones.
On the internet it always says you have to build an 80cm foundation.

What is correct now?

Regards
Speer

excavate, compact recycling in layers, pour foundation into formwork, lay stones on mortar. fill behind with recycling, compact in layers, and set another row of stones. place [noppenbahn] and drainage behind the last row.

how deep all this needs to be depends on your frost conditions. with a poorly insulated and heated basement, it might be like this or frost-free.

there's a lot you can do, and it will certainly hold.

The light shaft itself will be constructed in 3 rows with a distance of 30cm between the rows and each row having a height of 35cm. What is not quite clear to me now

... , is how to imagine that in cross-section.