You can create the Azure dashboard using template deployment in which Azure offers the ability to orchestrate the deployment of multiple resources.
Once the required resources for Azure Dashboard can be configured in template ARM template format, you can deploy using REST APIs, PowerShell, Azure CLI and Azure Portal template deployment.
This Microsoft Documentation helps you to create the Azure Dashboard using the Sample Templates given.
You can enable Health checks for your App Service using Azure Monitor App and that you can bring on Azure Dashboard to see your app service is up or down in the form of graph.
Source: Azure Service Health Dashboard