This video shows how to create and manage FTP accounts in DirectAdmin.
After entering the userame and password there is an access setting you have to pay attention to.
User would have access
to all file not just web files
under this domain.
User would have access to the
public_ftp folder but not website data.
This will create a folder based on their username
in the public_html folder of the default domain
which is set in the Domain Setup area.
Custom is the most useful because you can
specify exactly what a user has access to.