Hi Sumati-0206,
The link below will walk you through the entire process using the Azure CLI. I know you asked for PowerShell, but you can use it as a reference as there are many steps required if you are trying to fully script everything from containerization to deployment.
Tutorial: Build a custom image and run in App Service from a private registry
It looks like your App Service is running based on the portal messaging you received back, so the issue may be with publishing to the Azure Container Registry or creating the Web App from your container. To troubleshoot adding your container to the registry, please see this link which has instructions provided in PowerShell:
Quickstart: Create a private container registry using Azure PowerShell
If your container is uploading fine but you're having trouble deploying a Web App from it, check that you are including the container permissions when creating the Web App and that the permissions you are supplying can access the container. For more info you can refer to the New-AzureRmWebApp documentation:
Also, if you'd like your Web App to update every time there is a new container uploaded to the Azure Container Registry, go to the Container settings page of your App Service and turn on Continuous Deployment. You could always create the Web App manually once and then enable this setting if you were trying to automate updates to the same Web App.
Hope that helps!