How can I make such a thing?

I want to make a system that goes to each tile in my grid. checks for data that the tile store (like floats and bools) and then put objects on the tile using the data.
I want to use that to create a 3D map so for example:
the script goes to tile in x18 y0 and z23 and searches for height and block-type floats. the in found that the height float is 17 and the block type is 3. Then it put 17 blocks of type 3 on top of each other.
How can I make such a system using Unity?

would it basically look something like this?
- each x and z coordinate, in the grid, have certain height (but no empty gaps in those tall areas)

I think it would look pretty similar at least after the placement of blocks, depending on the tiles. I just want Unity to get data from the tiles and put above it cubes like in this picture. ofc to do such a thing the tile need to hold the height float and the type float. The idea is to use a 2D grid to make a 3D world

so you are using the Unity tilemap & grid components?

theres grid information extension, to store data,

if nothing else works,
you could have your own separate 3D array, where to store data, example:

I'll use the tutorial because I want to understand each step in the process but in the tutorial, He talks about "POCO model for tiles"? what is exactly a poco model for tiles?

oh interesting, haven't heard that before,
it is technically "Plain Old CLR Object" or "Plain Old Class Object" to avoid ties to specific languages or technologies