A custom module must make changes to the schema following each setup:upgrade run.
This must be done after all other module's schema updates have been applied.
How is this accomplished?

You are adding an entry to the backend menu. To do so you open a core etc/adminhtml/menu.xml file as a reference.
In the file you see the node:

What is the result of specifying resource="Magento_Catalog::catalog"?

You need to find all orders in the processing state. You have written the code:

When you run the code, you get the following exception:

How do you resolve the exception?

When creating a new payment method, the Adobe Commerce developer adds the dependency injection configuration for payment method facade in the modules etc\di.xml.
What is required for the custom payment methods Value Handlers pool?

You added a plugin declaration to MyCompany/MyModule/etc/di.xml:

What will be the effect of this declaration?