Email setup and password change
First step is to log in to your hosting control panel (cPanel).
Here you'll be able to adjust many aspects around the domain hosting, databases, DNS and also email settings.
Within the hosting control panel you'll see a Mail section. Here you can create new email boxes, add forwards/redirections and even set up auto responders independent of your email program/s.
Under Mail -> Mail Accounts is where you update the password for each email account.
Top right you'll find a help button that gives you useful info of the page you are on.
Email setup instructions is under the email accounts section as well.
In the email account list, on the right click the 'More' actions button on one of the accounts and select 'Configure Email Client'