Hello,
It looks like you are trying to install wrong archive (full package instead WP theme only). Read the post and follow the instructions https://help.market.envato.com/hc/en-us/articles/202821510-Theme-is-missing-the-style-css-stylesheet-error
Also, watch video tutorials https://www.youtube.com/playlist?list=PLMqMSqDgPNmCCyem_z9l2ZJ1owQUaFCE3
Regards
