Theme installed but not all there

I’m new to word-press, i just installed a new theme but it doesn’t appear to have installed it all correctly. I used a .zip. This is what it should appear like. https://themeforest.net/item/rockwell-portfolio-blog-wordpress-theme/full_screen_preview/249087

But it looks like this – https://www.newwavetv.co

I’ve trawled through the documentation and tried for hours to work it out, but I am failing miserably.

Any guidance much appreciated.