In your course you should see some sections at the left hand side.  Usually new courses will come with 10 blank sections named "Topic 1" through 10.

Rename Topics

To rename a section, you need to go into that section and click the button "Edit Section" to show the option to change the title and summary.  The summary is just text that shows up at the top of that page. 

Move Topics

Moving topics can be a bit unintuitive if you have never done this before. You probably won't need to rearrange the topics very often if ever, but here is how if you need to:

If you want to rearrange the sections of your course, click into one you want to move. 

Now that you have picked the section you want to move, it wants to know where you want to move it to. You need to click the link to the section in which you want to move this above.  Clicking the third topic will give you an option to move your page above the third topic.

Highlight Section

This is what a highlighted section looks like: