Have you installed the theme? Once you install the theme and enter the theme panel, you will see a yellow alert with a button that allows you to install the demo data.
Header (and the phone) can be edited from BurnEngine (Kiddos) CP > Page Builder > Header > Global. The phone is in fact an Icon List builder block.
Be aware that when you import the demo, all existing OpenCart data (products, categories, information pages etc.) will be replaced and you won’t be able to bring it back unless you restore a backup manually.