[Exim] Startup

Hi,
I'm just starting to learn exim.
Installed 4.30 on my debian server.

Could anyone give me an example of how to do
login in the configuration file (ACL section ?) ?
I donnot understand how that is done.
There's no simple sample in the docs.

At the moment all works fine, but I cannot do login
with my mail clients.

Thanks in advance,
Steven