Pretty simple. The outgoing server handles email that you are sending out,
and the incoming server handles email that is coming in to you.
Your mail provider (usually your ISP) determines the names and settings
for communicating with those mail servers. On their website will be
directions for setting up your email program.
In your case, it looks like Suddenlink.net is both your ISP and mail provider,
so go here for directions: https://account.suddenlink.net/selfcare/html/outlook-express-settings.html
Those directions are actually for Outlook Express, but will work fine with
Windows Mail also.