In FSTAB:
//192.168.188.52/media /home/shareuser/shared/ cifs vers=3.0,credentials=/home/shareuser/.smbcred,uid=1000,gid=1000,iocharset=utf8 0 0
In .smbcred are the credentials. The content of the file:
username=shareuser
password=shicjwvfiak domain=192.168.188.52
Should work.
Instead of the IP put the FQDN of your Share holding Server and make sure DNS is properly working.
Well not so much the adress of the AD server.
It should be the domain name of your domain that you have created.
As in Joh.Doe@CompanyWork.internal
The part behind the @ is the domain the user is registered to and even though the AD server might be named prod-ad-001 the text should be the domain you are trying to auth towards and the share you are accessing to should obvioisly have a connection the the AD to forward the credentials and ask if Auth is positive.