So I have this template that I've used to create my resource group. We are in the middle of development process, so it is pretty usual to add different resources from day to day.
How can I run the template to just add the ones that I am missing?
I've tried to deploy my template to my existing resource group, but I guess it just thinks that I want to create another set of resources.
What should I do?
ARM Templates are idempotent by default, so if you add resources to the template without changing anything else in it, it will just create\add new resources to your resource group. So that behavior is be default.
As for the parameters, it cannot magically infer the names (or anything) of things that you want to pass. You can either reuse existing deployments (it will prepopulate all the parameters), create a script that will pass in parameters, create a parameters file to pass in to the template.
Reference:
https://learn.microsoft.com/en-us/azure/azure-resource-manager/resource-group-template-deploy