Log in with your existing username and password by visiting https://skystreamhosting.com/mail. If this is your first time logging in, your temporary password would have been emailed to you along with setup instructions.
You'll be greeted by a log in screen that looks like this:

Once logged in, this what your webmail screen show look like.

In the main menu click on Others > My Account > Password.

You will be prompted to enter your current password, followed by your new password. Enter the information and click Change Password.

There is no step 4! You are finished.

Enjoy your email!