How can I find the credentials for this?
Please see image below.
I Tried to reproduce the same in my environment to connect using GMSA
First install ACTIVE DIRECTORY DOMAIN SERVICES and create service account for windows server using the below powershell.
Before executing the powershell script, kindly create one Security name GMSA-Test
PrincipalsAllowedToRetrieveManagedPassword is Security Group Name
Import-module ActiveDirectory
Add-KdsRootKey -EffectiveTime ((get-date).addhours(-10))
New-ADServiceAccount <youraccountname> -DNSHostName ITFarm1.contoso.com -PrincipalsAllowedToRetrieveManagedPassword <GMSA-Test> -KerberosEncryptionType RC4, AES128, AES256 -ServicePrincipalNames http/ITFarm1.contoso.com/contoso.com, http/ITFarm1.contoso.com/contoso, http/ITFarm1/contoso.com, http/ITFarm1/contoso
get-ADServiceAccount GMSAtest
Install ADServiceAccount using powershellon AAD Connect Server
Install-ADServiceAccount -Identity <youraccountname>
successfully created service account after ran the powershell commands.
Configure AAD connect with your Service Account.
Service Account Name: your domain\GMSAtest$ Password: PrincipalsAllowedToRetrieveManagedPassword
Reference: Using Azure AD Connect with a gMSA - The things that are better left unspoken (dirteam.com)