To deploy your app to an Azure resource, you need an Azure Resource Manager service connection first.
->Go to project setting of the new Project
->Service connections under Pipelines
->New Service Connection
->Select Azure Resource Manager
Then create a new pipeline to build the Beta service in the new project. Also note if you are using Azure Web App task to deploy your service you need to set the Azure Subscription field to Azure Resource Manager service connection created in the very first step. And you need to set appName field to new azure app service.
Want to become Azure Developer, check out this Microsoft Azure Training.