Introduction
It's easy to update your details. Here is how to do it.
Step 1
From the right side menu, click on your profile picture

Step 2
Click on the "Update Profile" menu item.

Your name, contact details, and address will load.
Step 3
Update your personal details as required.

Step 4
Click the blue Save Changes button when you are done.

You will have successfully updated your details.
NOTE: Unfortunately you will not be able to change your username.