I have added some links for you
https://learn.microsoft.com/en-us/azure/api-management/get-started-create-service-instance
https://learn.microsoft.com/en-us/ef/core/get-started/overview/first-app?tabs=netcore-cli
https://graphql-dotnet.github.io/docs/getting-started/introduction/
Please review
Entity Framework - can be used to connect to any relational databases including MS SQL and Azure SQL
GraphQL .NET - library that will help you build a GraphQL API in .NET Core. ou need to define a schema for your GraphQL API that will describe the types of data that can be queried
https://www.youtube.com/watch?v=HuN94qNwQmM&list=PLUQ4D25da8kGEK5zhIa9IKLCbAZ9bHM5F
ASP.NET Core Web API
Azure API Management - https://docs.microsoft.com/en-us/learn/modules/publish-manage-apis-with-azure-api-management/
these are the main topics you can concentrate