Rancher 2.7.6 PrometheusRules / AlertmanagerConfigs and routes

Hi there,
Trying to learn about how to setup prometheus rules and firing email alerts for now on namespace level using the GUI

I have created a PrometheusRule with ta PromQL Expression, this looks confirmed showing as Firing Alerts in Prometheus Alerts GUI

Added a label namespace:name

Created a secret for authenticating the email server password
Created an AlertmanagerConfigs
Receiver → Type Email, using our SMTP server and authentication creds
Matchers → namespace:name
Match Type → Match Equal

However I am not receiving any alerts in the email, our SMTP server is used for other different systems and is working

I am finding difficult to find related documentation with steps about how to create the rules and firing alerts, preferred via email

At the moment stuck, any given help will be very much appreciated