How to Configure Azure AD Connect Cloud Sync

does the Azure AD have to be installed in a domain comptuer?

hello, is it possible to SSO with a AAD joined Windows devices to a AADDS joined server ? thank you

I want to ask why my phs goes on quarantine all the time and the phs job Id are attached to all my object in the domain?

Thanks for the tutorial, should we still keep the original AD Connect Or is it okay to have just the cloud sync?