A cloud-based identity and access management service for securing user authentication and resource access
Hello Timothy,
For migrating local file servers and applications you should take a look at Azure Migrate:
https://learn.microsoft.com/en-us/azure/migrate/
For connecting your users to the Cloud you should be taking a look at Azure AD Connect to get your users off of local AD:
I would recommend starting by getting your users connected to the Cloud and ensure that the connection to Azure AD is solid. Then begin you migration of data to M365/Azure services.
Once you have everything working in M365/Azure, you can cut the hybrid connection and move to cloud only.
If this is helpful please accept answer.