How to use the concept of warehouse

I have two restaurant and I have a centralize SQL Database,means, using the same database of SambaPos4 for both restaurant. for this I create two departments rest1 and rest 2 and 3 warehouse (main warehouse, rest1 warehouse and rest2 warehouse) and transactions to move products between them. But I have problem creating inventory items, because I have to assoicate to a warehouse, but one product can be use in the three warehouses. When I try to create the same product for another warehose I receviede the message that already exsits. At the end I create the inventory without associate a ware house. Is this correct? or what is the idea of a warehouse?

Assigning a product to a warehouse is not required. You’ll assign it if you want to see a product listed under a certain warehouse inventory. For example you may want to Jack Daniels listed under only “Bar Inventory” not “Kitchen Inventory”.

I’m new to this. Please help out in planning. I have one restaurant, one kitchen and one warehouse. I have a bar. I sell drinks, alcoholic drinks, hot and cold appetizers and main dishes.

I’d like to use SambaPOS to track inventory and cost. I’m following this tutorial.

Question. What are warehouse types? I should create two warehouses, one for kitchen and one for bar if I want to have separate warehouse reports?