Place the label and buttons inside of an dataview pointed to an entity with an integer attribute. Create 2 nanoflows or microflows, depending on your use case. Both microflows will have a parameter that matches the entity of the dataview. The first microflow will have a change action that adds one to the attribute. The second microflow will have a change action that substracts one from the attribute. In the label (text widget), have a parameter for the text value that points to the integer attribute.
you may need to change your domain model. Each Product can be associated with multiple Product_Orders. Since you want to update the quantity in Product_Orders, this means you don’t know which one you should update. You can either change the association to a 1-1 or (my recommendation) put the quantity field in the Product entity, eliminate the Product_Orders entity and make a 1-* association between Product and Orders. With that structure, you will be able to update the quantity attribute on the Product entity with microflows as I described previously.
I have created a microflow and I call it when I click on the button. And I set the quaintity + 1, Can you check what is wrong?