1. After you log on Azure management portal, click on Settings in the lower left corner, check the screenshot below.
2. Click on Alerts link on the upper middle tab in the right pane, check the screenshot.
3. Click on Add Rule button in the lower tab, see the screenshot.
4. The below popup will appear , fill the name, description of the alert and then choose the service type that you want to monitor to filter the service name drop down to show the services of that type to choose from.
Note: the metrics appear in the second page is related to the service type you choose.
Happy Monitoring 🙂