Thanks Ivan. 

Is this just a bad training example or do I not understand what you try to achieve?

If it concerns a real use case: Are you familiar with basic MRP concepts? Do you know the workflows of your coffee shop? What kind of manufacturing has to be done? Do you have a bakery behind the POS or do you purchase the products to be sold? Do you want to plan on Sunday how many teas your waiter has to prepare on the next Thursday? Do you need to set up work orders for waiters preparing Latte Macchiatos in the shop or is it enough to have phantom BoMs to track the consumption of materials? Which products do you manufacture/purchase to stock? Which of these products are perishable, which not? What are your analytic accounting requirements?

MO, WO and BoM are artefacts to produce products (not days or anything strange), either to order or to stock.

My 25 years of experience implementing ERP systems tell me: if it reads like nonsense then it IS nonsense.

Maybe you want to make yourself familiar with the business case and MRP in general first and then ask specific Odoo related questions.