Next up is (someone)

This phrase introduces the next person who's going to speak at a meeting, the next performer in a theater, or the next set of athletes who are going to compete in a sports tournament:

Next up is a man who needs no introduction. Ladies and gentlemen, put your hands together for Trey Faust!

Next up is the champion, Marla Needham, against newcomer Erin Spanner.

walk (someone) through (something)

When you "walk through" something, you talk about it step-by-step. In the example above, the speaker says that his coworker is going to walk everyone through a new home page. That means that he's going to show them each new feature of the site. Some other examples of "walking through" something include:

• When you're preparing for a wedding, you usually walk everyone through what to do during the ceremony.
• You should walk your children through what to do in case of an emergency like a fire.

a home page redesign

The "home page" of a website is the first page that you see when you visit that site.

A "web page redesign" is when someone changes how a web page looks or works.