If you've installd TheMAG using Simple Installation method, after restoring the database your account username and password are overridden with username: demo, password: demo. It is highly recommended to change those data.
Go to your profile page
/user/1 and click on the Edit tab.
Under th Account tab, set the new username, password and email address.
Click on the Personal Info tab, upload image for your profile, choose account display name and write a short bio for your self. This informations will be shown on your profile a.k.a. author's page and also will be used as a signature for your posts.
Under Social Media Pages tab you can add your social media profile pages that you wish to be shown on your profile page.