modify a POS Manager module

I have a module that I'm currently using in Odoo 14.0 (Community Edition) but I want to modify it by adding others actions, the module I use allows to block actions on the POS by password, I want the module on the quantity button to work at first time, that means when opening POS the quantity button allows to add a quantity on an article, but if I want to delete the quantity I have to ask a password and if the quantity is lower or less , you have to ask for the password, and also when asking for the password I want to use a badge that contains the password, so I will use a barcode scanner to identify the password.

attached screenshot of Pos Manager module.