Hi,

To add a new button to the POS screen interface in Odoo, you need to define a new widget and then add it to the POS view. The code you provided is incomplete, but it appears that you have defined a class named "waiter" with its views, but you have not added it to the POS view.

To add the button, you can follow the steps in this blog post:

https://www.cybrosys.com/blog/how-to-add-a-custom-button-in-the-pos-screen-odoo-16. 

It provides a step-by-step guide on how to add a custom button to the POS screen using a widget.

In summary, you need to create a new widget for your button, which will contain the HTML code for the button and the JavaScript code to handle its click event. Then, you need to add the widget to the POS view by extending the "pos" model and adding the new widget to its "template" attribute. Finally, you need to define a new action for the button in the "pos.config" model.

Refer to the blog post for detailed instructions and code samples.

Regards

I added this but it seems not to be working the pos screen interface dosn't show for me ,what am I missing please?

{
model: 'pos.waiter',
fields: ['name'],
domain: null,
loaded: function(self, waiter){
self.waiter = waiter;
self.db.add_waiter(waiter);
}

"widget.pos.waiter"  <-- How can your 'waiter' get into 'widget.pos'?

Everything needs to be loaded before using. Please take a look at point_of_sale/static/src/js/models.js to see how data is fetched.