Enroll BULK Intune devices

Hello, we need to add about 1500 devices to Intune. The devices are mounted in a local domain and some of them are also mounted in Azure AD.

Now I do not know my way around yet.
What is the easiest way to add the devices to Intune?

And how can I easily configure new devices so that software etc. is installed directly?

Please help me! I appreciate any help!