Read Chapter 15-Messaging in the Administration guide. It has everything you need to setup SMTP email messaging.
In the MAIL.INI file, you need to set four parameters. For the "email" and "displayname" use the email address and human readable name you want Asset Manager to connect to the email server with. These will be the "FROM" address on any email coming from AM.
Depending on your email security settings you may need to get this account created and authorized on the email servers for them to accept email from Asset Manager.
A MAIL.INI file having these lines...
displayname=Asset Manager (do not reply)
...would send an email with this FROM addressee...
FROM: Asset Manager (do not reply) <AssetManager@mydomain.net>
Please refer to the following technote to help you understand this feature.