Honestly, I find the Odoo location structure overcomplicated. I cannot get my head around it so I am asking for help...

Our setup and goal is pretty common and straightforward. We have a database with thousands of articles where we need to manage the stock and sales process. Stock management is done in Odoo Inventory, Sales in POS module. So when we sell an article it is scanned in the POS module, and we want the quantity to be automatically deducted in the inventory in Odoo. Pretty simple but currently it's not working. I suspect it is because of the poor setup of our location structure. I cannot find any good document or tutorial on how to simply set up the warehouses and locations as in my example.

Our wanted location structure:

Multiple warehouses: 1 2 3 4

Inside every warehouse there are different locations (shelves or racks) like

1.A1, 1.A2, 1.A3,...
2.A1, 2.A2, 2.A3,...
3.A1, 3.A2, 3.A3,...
4.A1, 4.A2, 4.A3,...

So it is Warehouse -> Locations

The question is how to set this up properly so the POS takes in account these locations and deducts quantities properly when sold. I also hope to set reordering rules after that is fixed so things can be reordered when they go below a certain quantity...