It's very easy to rename the pages of your website. First login to your dashboard, and click on Manage Pages
Then, next to the page you want to rename, click edit
Rename the page to what you desire, and click save
Now you can go to Preview Mode, and see that your page has been renamed.
If you want to change the page order in your menu just click on the little arrows in the order column and drag the page to the position you require.
You can also change your page URL, view our guide on changing page URLs and Page redirects.