You'll need an E-mail client, such as Thunderbird (for desktop), or Spark (for mobile).
In this example, myname will be your username, hence your
E-mail will be myname@knutsen.co.
Note that these are not the same
Your password should already be known, and can be changed at user.knutsen.co.
Your incoming server will be IMAP, and your outgoing will be SMTP, naturally.
mail.knutsen.co:993 over SSL/TLSmynamemail.knutsen.co:587 over STARTTLSmynameHere is an example Thunderbird configuration: