Make sure that you are logged in to your user account. You can click here to login.
On your user profile page, you should see a list of your pages and projects (if you are entitled to add projects). To the right of each of your pages is an 'Edit' link. Click on the 'Edit' link to make changes to that particular page.
Once you have finished making your changes, click on the 'Save' button to save the changes.