How to modify About Us page in nopCommerce?

My tasks:
1) Show the About Us link in top menu.
2) Change the About Us page to only one column.
3) Modify the contents in About Us.

There is already an About Us page created in nopCommerce, so we can just make use of that page without creating a new one.

1. Go to Administration > Content Management > Topics (Pages)

2. Click on the Edit button for AboutUs page - modify the contents and check include in top menu.

3. Look for the file : \Presentation\Nop.Web\Views\Topic\TopicDetails.cshtml

Change this code to:
Layout = "~/Views/Shared/_ColumnsOne.cshtml";